Brian Eaton, Jonathan Gregory et. al. This is an ontology representation for the Climate and Forecast (CF) standard names parameter vocabulary, which is intended for use with climate and forecast data, in the atmosphere, surface and ocean domains More information: http://www.cgd.ucar.edu/cms/eaton/cf-metadata/standard_name.xml 2007-03-09T17:52:04+0000 Luis Bermudez MMI Parameters version 2007-03-09T17:52:02+0000 Climate and Forecast (CF) standard names parameter vocabulary Standard Name GRIB AMIP Standard Name Description Runoff is the liquid water which drains from land. If not specified, "runoff" refers to the sum of surface runoff and subsurface drainage. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. mrro kg m-2 s-1 runoff_flux runoff_flux "stp" means standard temperature (0 degC) and pressure (101325 Pa). "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. The equivalent thickness at STP of a particular constituent of the atmosphere is the thickness of the layer that the gas would occupy if it was separated from the other constituents and gathered together at STP. 10 m equivalent_thickness_at_stp_of_atmosphere_ozone_content equivalent_thickness_at_stp_of_atmosphere_ozone_content The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area. Runoff is the liquid water which drains from land. If not specified, "runoff" refers to the sum of surface runoff and subsurface drainage. 90 kg m-2 surface_runoff_amount surface_runoff_amount "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. W m-2 tendency_of_dry_static_energy_content_of_atmosphere_layer tendency_of_dry_static_energy_content_of_atmosphere_layer "Northward" indicates a vector component which is positive when directed northward (negative southward). "Upward" indicates a vector component which is positive when directed upward (negative downward). "Upward northward" indicates the ZY component of a tensor. An upward northward stress is an upward flux of northward momentum, which accelerates the upper medium northward and the lower medium southward. Pa upward_northward_stress_at_sea_ice_base upward_northward_stress_at_sea_ice_base "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. evspsbl water_evaporation_flux water_evaporation_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "tendency_of_X" means derivative of X with respect to time. "longwave" means longwave radiation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. K s-1 tendency_of_air_temperature_due_to_longwave_heating_assuming_clear_sky tendency_of_air_temperature_due_to_longwave_heating_assuming_clear_sky The surface called "surface" means the lower boundary of the atmosphere. Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. K surface_temperature_where_snow surface_temperature_where_snow Sea surface wave variance spectral density is the variance of wave amplitude within a range of wave frequency. m2 s-1 sea_surface_wave_variance_spectral_density sea_surface_wave_variance_spectral_density "product_of_X_and_Y" means X*Y. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. K Pa s-1 product_of_air_temperature_and_omega product_of_air_temperature_and_omega Vapor pressure is the partial pressure of a constituent of air, such as water, which exists as liquid or solid under "normal" conditions. "Water" is specified when the term is being applied to water. 55 water_vapor_pressure water_vapor_pressure Speed is the magnitude of velocity. 48 m s-1 sea_water_speed sea_water_speed "shortwave" means shortwave radiation. "toa" means top of atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rst toa_net_downward_shortwave_flux toa_net_downward_shortwave_flux W m-2 m-1 sr-1 Mole fraction is used in the construction mole_fraction_of_X_in_Y, where X is a material constituent of Y. tro3 1 mole_fraction_of_ozone_in_air mole_fraction_of_ozone_in_air "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) geostrophic_eastward_wind geostrophic_eastward_wind Thermal conductivity is the constant k in the formula q = -k grad T where q is the heat transfer per unit time per unit area of a surface normal to the direction of transfer and grad T is the temperature gradient. Thermal conductivity is a property of the material. W m-1 K-1 soil_thermal_conductivity soil_thermal_conductivity "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. atmosphere_sulfate_content atmosphere_sulfate_content "direction_of_X" means direction of a vector, a bearing. A velocity is a vector quantity. 47 degree direction_of_sea_water_velocity direction_of_sea_water_velocity Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. degree s-1 platform_yaw_rate platform_yaw_rate time s time time J kg-1 K-1 The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. W m-2 sr-1 surface_upwelling_radiance_in_sea_water surface_upwelling_radiance_in_sea_water "condensed_water" means liquid and ice. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. cloud_condensed_water_content_of_atmosphere_layer cloud_condensed_water_content_of_atmosphere_layer mol m-2 s-1 m-1 sr-1 "Northward" indicates a vector component which is positive when directed northward (negative southward). "Atmosphere heat transport" means total heat transport by the atmosphere by all processes. W northward_atmosphere_heat_transport northward_atmosphere_heat_transport "product_of_X_and_Y" means X*Y. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. It is numerically similar to the altitude (or geometric height) and not to the quantity with standard name height, which is relative to the surface. "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. Pa m s-1 product_of_geopotential_height_and_omega product_of_geopotential_height_and_omega The surface called "surface" means the lower boundary of the atmosphere. 66 snd surface_snow_thickness surface_snow_thickness Pa-1 s-1 "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. water_vapor_content_of_atmosphere_layer water_vapor_content_of_atmosphere_layer "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. Omnidirectional spherical irradiance is the radiation incident on unit area of a spherical (or "4-pi") collector. It is sometimes called "scalar irradiance". Radiation incident on a 2-pi collector has standard names of "spherical irradiance" which specify up/downwelling. omnidirectional_photosynthetic_spherical_irradiance_in_sea_water omnidirectional_photosynthetic_spherical_irradiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. "shortwave" means shortwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rss surface_net_downward_shortwave_flux surface_net_downward_shortwave_flux "shortwave" means shortwave radiation. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Net absorbed radiation is the difference between absorbed and emitted radiation. net_rate_of_absorption_of_shortwave_energy_in_atmosphere_layer net_rate_of_absorption_of_shortwave_energy_in_atmosphere_layer "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". cl cloud_area_fraction_in_atmosphere_layer cloud_area_fraction_in_atmosphere_layer ocean_isopycnal_layer_thickness_diffusivity ocean_isopycnal_layer_thickness_diffusivity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. tendency_of_water_vapor_content_of_atmosphere_layer_due_to_shallow_convection tendency_of_water_vapor_content_of_atmosphere_layer_due_to_shallow_convection The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. tendency_of_water_vapor_content_of_atmosphere_layer_due_to_deep_convection tendency_of_water_vapor_content_of_atmosphere_layer_due_to_deep_convection Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.). tropopause_instantaneous_radiative_forcing tropopause_instantaneous_radiative_forcing "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. horizontal_dry_energy_transport_in_atmosphere_layer horizontal_dry_energy_transport_in_atmosphere_layer A velocity is a vector quantity. "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. The vertical mean land ice velocity is the average from the bedrock to the surface of the ice. land_ice_vertical_mean_y_velocity land_ice_vertical_mean_y_velocity The term "Exner function" is applied to various quantities in the literature. "Dimensionless Exner function" is the standard name of (p/p0)^(R/Cp), where p is pressure, p0 a reference pressure, R the gas constant and Cp the specific heat at constant pressure. This quantity is also the ratio of in-situ to potential temperature. Standard names for other variants can be defined on request. dimensionless_exner_function dimensionless_exner_function The surface called "surface" means the lower boundary of the atmosphere. "longwave" means longwave radiation. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 112 E176 surface_net_upward_longwave_flux surface_net_upward_longwave_flux Model level number should be understood as equivalent to layer number. lev model_level_number model_level_number The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. surface_albedo_assuming_no_snow surface_albedo_assuming_no_snow A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. net_upward_shortwave_flux_in_air_assuming_clear_sky net_upward_shortwave_flux_in_air_assuming_clear_sky Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. horizontal_atmosphere_dry_energy_transport horizontal_atmosphere_dry_energy_transport "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. The land ice calving rate is the rate at which ice is lost per unit area through calving into the ocean. land_ice_calving_rate land_ice_calving_rate The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) m s-2 tendency_of_northward_wind_due_to_diffusion tendency_of_northward_wind_due_to_diffusion kg m-3 concentration_of_suspended_matter_in_sea_water concentration_of_suspended_matter_in_sea_water "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. volume_fraction_of_sand_in_soil volume_fraction_of_sand_in_soil Swell waves are waves on the ocean surface. "to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. 104 sea_surface_swell_wave_to_direction sea_surface_swell_wave_to_direction Height is the vertical distance above the surface. Swell waves are waves on the ocean surface. 105 sea_surface_swell_wave_significant_height sea_surface_swell_wave_significant_height In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The atmosphere convective mass flux is the vertical transport of mass for a field of cumulus clouds or thermals, given by the product of air density and vertical velocity. For an area-average, cell_methods should specify whether the average is over all the area or the area of updrafts only. atmosphere_convective_mass_flux atmosphere_convective_mass_flux "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) Potential evaporation is the rate at which evaporation would take place under unaltered ambient conditions (temperature, relative humidity, wind, etc.) if the supply of water were unlimited, as if from an open water surface. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_potential_evaporation_flux water_potential_evaporation_flux A velocity is a vector quantity. "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. sea_ice_y_velocity sea_ice_y_velocity The radiation wavelength can refer to any electromagnetic wave, such as light, heat radiation and radio waves. radiation_wavelength radiation_wavelength The surface called "surface" means the lower boundary of the atmosphere. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "wrt" means with respect to. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. See Appendix D of the CF convention for information about dimensionless vertical coordinates. J m-2 change_in_energy_content_of_atmosphere_layer_due_to_change_in_sigma_coordinate_wrt_surface_pressure change_in_energy_content_of_atmosphere_layer_due_to_change_in_sigma_coordinate_wrt_surface_pressure The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area. "Water" means water in all phases, including frozen i.e. ice and snow. Surface amount refers to the amount on the ground, excluding that on the plant or vegetation canopy. surface_water_amount surface_water_amount The surface called "surface" means the lower boundary of the atmosphere. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). "Downward" indicates a vector component which is positive when directed downward (negative upward). "Downward eastward" indicates the ZX component of a tensor. A downward eastward stress is a downward flux of eastward momentum, which accelerates the lower medium eastward and the upper medium westward. The surface downward stress is the windstress on the surface. E180 tauu surface_downward_eastward_stress surface_downward_eastward_stress "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". The cloud area fraction is for the whole atmosphere column, as seen from the surface or the top of the atmosphere. The cloud area fraction in a layer of the atmosphere has the standard name cloud_area_fraction_in_atmosphere_layer. The ISCCP cloud area fraction is diagnosed from atmosphere model output by the ISCCP simulator software in such a way as to be comparable with the observational diagnostics of ISCCP (the International Satellite Cloud Climatology Project). clisccp isccp_cloud_area_fraction isccp_cloud_area_fraction "shortwave" means shortwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. tropopause_net_downward_shortwave_flux tropopause_net_downward_shortwave_flux "product_of_X_and_Y" means X*Y. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. Pa s-1 product_of_specific_humidity_and_omega product_of_specific_humidity_and_omega Solar zenith angle is the the angle between the line of sight to the sun and the local vertical. solar_zenith_angle solar_zenith_angle "Amount" means mass per unit area. large_scale_rainfall_amount large_scale_rainfall_amount planetary_albedo planetary_albedo A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rlntpcs net_upward_longwave_flux_in_air_assuming_clear_sky net_upward_longwave_flux_in_air_assuming_clear_sky The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Spherical irradiance is the radiation incident on unit area of a hemispherical (or "2-pi") collector. It is sometimes called "scalar irradiance". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of "omnidirectional spherical irradiance". W m-2 m-1 surface_downwelling_spectral_spherical_irradiance_in_sea_water surface_downwelling_spectral_spherical_irradiance_in_sea_water "moisture" means water in all phases contained in soil. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Quantities defined for a soil layer must have a vertical coordinate variable with boundaries indicating the extent of the layer(s). The field capacity of soil is the maximum content of water it can retain against gravitational drainage. mrsofcs moisture_content_of_soil_layer_at_field_capacity moisture_content_of_soil_layer_at_field_capacity Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. 6 E129 m2 s-2 geopotential geopotential Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upwelling_spectral_radiative_flux_in_air upwelling_spectral_radiative_flux_in_air "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". Convective cloud is that produced by the convection schemes in an atmosphere model. convective_cloud_area_fraction_in_atmosphere_layer convective_cloud_area_fraction_in_atmosphere_layer large_scale_rainfall_rate large_scale_rainfall_rate The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The vertical heat flux in air is the sum of all heat fluxes i.e. radiative, latent and sensible. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. hfns surface_downward_heat_flux_in_air surface_downward_heat_flux_in_air "Upward" indicates a vector component which is positive when directed upward (negative downward). The sea ice basal heat flux is the vertical heat flux (apart from radiation i.e. "diffusive") in sea water at the base of the sea ice. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_sea_ice_basal_heat_flux upward_sea_ice_basal_heat_flux "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. enthalpy_content_of_atmosphere_layer enthalpy_content_of_atmosphere_layer "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). aerosol_angstrom_exponent aerosol_angstrom_exponent Sea water density is the in-situ density (not the potential density). If 1000 kg m-3 is subtracted, the standard name sea_water_sigma_t should be chosen instead. sea_water_density sea_water_density The surface called "surface" means the lower boundary of the atmosphere. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "wrt" means with respect to. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. "Atmosphere energy content" has not yet been precisely defined! Please express your views on this quantity on the CF email list. See Appendix D of the CF convention for information about dimensionless vertical coordinates. change_in_atmosphere_energy_content_due_to_change_in_sigma_coordinate_wrt_surface_pressure change_in_atmosphere_energy_content_due_to_change_in_sigma_coordinate_wrt_surface_pressure The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). s-1 tendency_of_mass_fraction_of_cloud_ice_in_air_due_to_diffusion tendency_of_mass_fraction_of_cloud_ice_in_air_due_to_diffusion degree_east The unit of salinity is PSU, which is dimensionless. The units attribute should be given as 1e-3 or 0.001 i.e. parts per thousand if salinity is in PSU. 88 so 1e-3 sea_water_salinity sea_water_salinity m2 The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Photon radiance is the photon flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. A photon flux is specified in terms of numbers of photons expressed in moles. mol m-2 s-1 sr-1 surface_downwelling_photon_radiance_in_sea_water surface_downwelling_photon_radiance_in_sea_water m3 sea_ice_volume sea_ice_volume "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_sigma_coordinate land_ice_sigma_coordinate The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Spherical irradiance is the radiation incident on unit area of a hemispherical (or "2-pi") collector. It is sometimes called "scalar irradiance". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of "omnidirectional spherical irradiance". surface_downwelling_spherical_irradiance_in_sea_water surface_downwelling_spherical_irradiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. E134 ps surface_air_pressure surface_air_pressure degree_north s-2 The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Atmosphere_Xward_stress is a stress which tends to accelerate the atmosphere in direction X. tauugwd atmosphere_eastward_stress_due_to_gravity_wave_drag atmosphere_eastward_stress_due_to_gravity_wave_drag The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. mol m-2 s-1 m-1 surface_downwelling_spectral_photon_flux_in_sea_water surface_downwelling_spectral_photon_flux_in_sea_water "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. 54 prw atmosphere_water_vapor_content atmosphere_water_vapor_content cloud_base refers to the base of the lowest cloud. Convective cloud is that produced by the convection schemes in an atmosphere model. air_pressure_at_convective_cloud_base air_pressure_at_convective_cloud_base m3 s-2 Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. "Water" means water in all phases. "Canopy" means the plant or vegetation canopy. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. evspsblveg water_evaporation_flux_from_canopy_where_land water_evaporation_flux_from_canopy_where_land atmosphere_momentum_diffusivity atmosphere_momentum_diffusivity "Amount" means mass per unit area. The construction thickness_of_[X_]rainfall_amount means the accumulated "depth" of rainfall i.e. the thickness of a layer of liquid water having the same mass per unit area as the rainfall amount. thickness_of_large_scale_rainfall_amount thickness_of_large_scale_rainfall_amount The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Photon spherical irradiance is the photon flux incident on unit area of a hemispherical (or "2-pi") collector. A photon flux is specified in terms of numbers of photons expressed in moles. mol m-2 s-1 surface_downwelling_photon_spherical_irradiance_in_sea_water surface_downwelling_photon_spherical_irradiance_in_sea_water "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. lwe_thickness_of_large_scale_snowfall_amount lwe_thickness_of_large_scale_snowfall_amount Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. downwelling_spectral_radiance_in_air downwelling_spectral_radiance_in_air Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. 8 altitude altitude Fractional saturation is the ratio of some measure of concentration to the saturated value of the same quantity. fractional_saturation_of_oxygen_in_sea_water fractional_saturation_of_oxygen_in_sea_water Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_snow_in_air mass_fraction_of_snow_in_air "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_sea_ice_basal_salt_flux downward_sea_ice_basal_salt_flux "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". The cloud area fraction is for the whole atmosphere column, as seen from the surface or the top of the atmosphere. The cloud area fraction in a layer of the atmosphere has the standard name cloud_area_fraction_in_atmosphere_layer. 71 E164 clt cloud_area_fraction cloud_area_fraction "lwe" means liquid water equivalent. lwe_large_scale_snowfall_rate lwe_large_scale_snowfall_rate A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. "toa" means top of atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. toa_net_upward_longwave_flux_assuming_clear_sky toa_net_upward_longwave_flux_assuming_clear_sky Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. The equilibrium line is the locus of points on a land ice surface at which ice accumulation balances ice ablation over the year. equilibrium_line_altitude equilibrium_line_altitude "Water" means water in all phases. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_water_in_air mass_fraction_of_water_in_air Speed is the magnitude of velocity. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) The wind speed is the magnitude of the wind velocity. A gust is a sudden brief period of high wind speed. In an observed timeseries of wind speed, the gust wind speed can be indicated by a cell_methods of maximum for the time-interval. In an atmospheric model which has a parametrised calculation of gustiness, the gust wind speed may be separately diagnosed from the wind speed. wind_speed_of_gust wind_speed_of_gust The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area. 99 surface_snow_melt_amount surface_snow_melt_amount "Northward" indicates a vector component which is positive when directed northward (negative southward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. northward_water_vapor_flux northward_water_vapor_flux The surface called "surface" means the lower boundary of the atmosphere. "anomaly" means difference from climatology. The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. surface_temperature_anomaly surface_temperature_anomaly m-1 s-1 "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_evaporation_flux_from_soil water_evaporation_flux_from_soil moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y. mol kg-1 moles_of_phosphate_per_unit_mass_in_sea_water moles_of_phosphate_per_unit_mass_in_sea_water "lwe" means liquid water equivalent. lwe_precipitation_rate lwe_precipitation_rate The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by diffusion means the part due to horizontal or isopyncal diffusion schemes in an ocean model, but not including the "bolus" or Gent-McWilliams velocity. kg s-1 northward_ocean_freshwater_transport_due_to_diffusion northward_ocean_freshwater_transport_due_to_diffusion "product_of_X_and_Y" means X*Y. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpuva product_of_eastward_wind_and_northward_wind product_of_eastward_wind_and_northward_wind "Northward" indicates a vector component which is positive when directed northward (negative southward). Ocean transport means transport by all processes, both sea water and sea ice. northward_ocean_salt_transport northward_ocean_salt_transport The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by (meridional) overturning is geometrically defined as being the part due to the vertical integral of the product of zonal means of velocity and tracer. The velocity does not include "bolus" or Gent-McWilliams velocity. sltovovrt northward_ocean_salt_transport_due_to_overturning northward_ocean_salt_transport_due_to_overturning See Appendix D of the CF convention for information about dimensionless vertical coordinates. atmosphere_hybrid_sigma_pressure_coordinate atmosphere_hybrid_sigma_pressure_coordinate "shortwave" means shortwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. net_downward_shortwave_flux_in_air net_downward_shortwave_flux_in_air The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tendency_of_air_temperature_due_to_advection tendency_of_air_temperature_due_to_advection "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. 58 clivi atmosphere_cloud_ice_content atmosphere_cloud_ice_content Fluxes at the top_of_atmosphere_model differ from TOA fluxes only if the model TOA fluxes make some allowance for the atmosphere above the top of the model; if not, it is usual to give standard names with toa to the fluxes at the top of the model atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rtmt net_downward_radiative_flux_at_top_of_atmosphere_model net_downward_radiative_flux_at_top_of_atmosphere_model "Amount" means mass per unit area. The construction thickness_of_[X_]snowfall_amount means the accumulated "depth" of snow which fell i.e. the thickness of the layer of snow at its own density. There are corresponding standard names for liquid water equivalent (lwe) thickness. thickness_of_convective_snowfall_amount thickness_of_convective_snowfall_amount The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. The partial pressure of a gaseous constituent of air is the pressure which it alone would exert with unchanged temperature and number of moles per unit volume. surface_carbon_dioxide_partial_pressure_difference_between_air_and_sea_water surface_carbon_dioxide_partial_pressure_difference_between_air_and_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tnmmvc tendency_of_northward_wind_due_to_convection tendency_of_northward_wind_due_to_convection "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) Wind shear is the derivative of wind with respect to height. 46 northward_wind_shear northward_wind_shear Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). In an atmosphere model, stratiform cloud is that produced by large-scale convergence (not the convection schemes). mass_fraction_of_stratiform_cloud_ice_in_air mass_fraction_of_stratiform_cloud_ice_in_air Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. Scattering of radiation is its deflection from its incident path without loss of energy. The volume scattering function is the fraction of incident radiative flux scattered into unit solid angle per unit path length. The (range of) direction(s) of scattering can be specified by a coordinate of scattering_angle. m-1 sr-1 volume_scattering_function_of_radiative_flux_in_sea_water volume_scattering_function_of_radiative_flux_in_sea_water "Northward" indicates a vector component which is positive when directed northward (negative southward). "Downward" indicates a vector component which is positive when directed downward (negative upward). "Downward northward" indicates the ZY component of a tensor. Momentum flux is dimensionally equivalent to stress and pressure. It is a tensor quantity. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 125 downward_northward_momentum_flux_in_air downward_northward_momentum_flux_in_air "Amount" means mass per unit area. convective_rainfall_amount convective_rainfall_amount The surface called "surface" means the lower boundary of the atmosphere. "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. Surface amount refers to the amount on the ground, excluding that on the plant or vegetation canopy. E141 lwe_thickness_of_surface_snow_amount lwe_thickness_of_surface_snow_amount Hydraulic conductivity is the constant k in Darcy's Law q=-k grad h for fluid flow q (volume transport per unit area i.e. velocity) through a porous medium, where h is the hydraulic head (pressure expressed as an equivalent depth of water). soil_hydraulic_conductivity_at_saturation soil_hydraulic_conductivity_at_saturation Sound pressure is the difference from the local ambient pressure caused by a sound wave at a particular location and time. Sound pressure level in water is expressed on a logarithmic scale with reference to a sound pressure of 1e-6 Pa. Lp = 20 log10(p/p0) where Lp is the sound pressure level, p is the rms sound pressure and p0 is the reference sound pressure. dB sound_pressure_level_in_water sound_pressure_level_in_water The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The surface latent heat flux is the exchange of heat between the surface and the air on account of evaporation (including sublimation). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downward_latent_heat_flux surface_downward_latent_heat_flux A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). baroclinic_northward_sea_water_velocity baroclinic_northward_sea_water_velocity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. tendency_of_specific_humidity_due_to_diffusion tendency_of_specific_humidity_due_to_diffusion The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Upward" indicates a vector component which is positive when directed upward (negative downward). Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_dry_static_energy_flux_due_to_diffusion upward_dry_static_energy_flux_due_to_diffusion Wind waves are waves on the ocean surface. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) "to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. 101 sea_surface_wind_wave_to_direction sea_surface_wind_wave_to_direction The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by diffusion means the part due to horizontal or isopyncal diffusion schemes in an ocean model, but not including the "bolus" or Gent-McWilliams velocity. htovdiff northward_ocean_heat_transport_due_to_diffusion northward_ocean_heat_transport_due_to_diffusion "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_thickness land_ice_thickness Air temperature is the bulk temperature of the air, not the surface (skin) temperature. Air temperature excess and deficit are calculated relative to the air temperature threshold. air_temperature_threshold air_temperature_threshold "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. "Vegetation" means any plants e.g. trees, shrubs, grass. 87 vegetation_area_fraction vegetation_area_fraction The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tnmmugwd tendency_of_eastward_wind_due_to_gravity_wave_drag tendency_of_eastward_wind_due_to_gravity_wave_drag "Northward" indicates a vector component which is positive when directed northward (negative southward). Ocean transport means transport by all processes, both sea water and sea ice. northward_ocean_heat_transport northward_ocean_heat_transport Latitude is positive northward; its units of degree_north (or equivalent) indicate this explicitly. In a latitude-longitude system defined with respect to a rotated North Pole, the standard name of grid_latitude should be used instead of latitude. Grid latitude is positive in the grid-northward direction, but its units should be plain degree. grid_latitude grid_latitude "ln_X" means natural logarithm of X. X must be dimensionless. See Appendix D of the CF convention for information about dimensionless vertical coordinates. atmosphere_ln_pressure_coordinate atmosphere_ln_pressure_coordinate moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y. moles_of_silicate_per_unit_mass_in_sea_water moles_of_silicate_per_unit_mass_in_sea_water A variable with the standard name of region contains strings which indicate geographical regions. These strings must be chosen from the standard region list. string region region "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. tendency_of_atmosphere_dry_energy_content tendency_of_atmosphere_dry_energy_content cloud_base refers to the base of the lowest cloud. Height is the vertical distance above the surface. Convective cloud is that produced by the convection schemes in an atmosphere model. convective_cloud_base_height convective_cloud_base_height The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downward_heat_flux_in_sea_water surface_downward_heat_flux_in_sea_water "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. W m-1 eastward_atmosphere_dry_static_energy_transport_across_unit_distance eastward_atmosphere_dry_static_energy_transport_across_unit_distance The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area. "Water" means water in all phases, including frozen i.e. ice and snow. "Canopy" means the plant or vegetation canopy. "Canopy and surface water" means the sum of water on the ground and on the canopy. canopy_and_surface_water_amount canopy_and_surface_water_amount "tendency_of_X" means derivative of X with respect to time. A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). Upward air velocity is the vertical component of the 3D air velocity vector. tendency_of_upward_air_velocity tendency_of_upward_air_velocity "to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. sea_surface_wave_to_direction sea_surface_wave_to_direction A velocity is a vector quantity. "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_y_velocity land_ice_y_velocity Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. downwelling_spectral_radiance_in_sea_water downwelling_spectral_radiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. "change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. "Amount" means mass per unit area. Surface amount refers to the amount on the ground, excluding that on the plant or vegetation canopy. change_over_time_in_surface_snow_amount change_over_time_in_surface_snow_amount "Water" means water in all phases. The water flux or volume transport into the ocean from rivers is the inflow to the ocean, often applied to the surface in ocean models. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_flux_into_ocean_from_rivers water_flux_into_ocean_from_rivers Sound pressure is the difference from the local ambient pressure caused by a sound wave at a particular location and time. sound_pressure_in_water sound_pressure_in_water Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. upwelling_spectral_radiance_in_air upwelling_spectral_radiance_in_air Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The volume scattering/absorption/attenuation coefficient is the fractional change of radiative flux per unit path length due to the stated process. Coefficients with canonical units of m2 s-1 i.e. multiplied by density have standard names with specific_ instead of volume_. The scattering/absorption/attenuation coefficient is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength is included to specify the wavelength. Scattering of radiation is its deflection from its incident path without loss of energy. Backwards scattering refers to the sum of scattering into all backward angles i.e. scattering_angle exceeding pi/2 radians. A scattering_angle should not be specified with this quantity. m-1 volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water "product_of_X_and_Y" means X*Y. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. mpwhusa product_of_omega_and_specific_humidity product_of_omega_and_specific_humidity ocean_volume ocean_volume The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Speed is the magnitude of velocity. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) The wind speed is the magnitude of the wind velocity. tendency_of_wind_speed_due_to_convection tendency_of_wind_speed_due_to_convection Pa m s-2 Dew point temperature is the temperature at which a parcel of air reaches saturation upon being cooled at constant pressure and specific humidity. 17 dew_point_temperature dew_point_temperature Potential temperature is the temperature a parcel of air or sea water would have if moved adiabatically to sea level pressure. equivalent_potential_temperature equivalent_potential_temperature "Content" indicates a quantity per unit area. "Vegetation" means any plants e.g. trees, shrubs, grass. vegetation_carbon_content vegetation_carbon_content A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Sea ice velocity is defined as a two-dimensional vector, with no vertical component. 95 eastward_sea_ice_velocity eastward_sea_ice_velocity "specific" means per unit mass. Potential energy is the sum of the gravitational potential energy relative to the geoid and the centripetal potential energy. (The geopotential is the specific potential energy.) Convective(ly) available potential energy is often abbreviated as "CAPE". J kg-1 atmosphere_specific_convective_available_potential_energy atmosphere_specific_convective_available_potential_energy "Water" means water in all phases. Flux correction is also called "flux adjustment". A positive flux correction is downward i.e. added to the ocean. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_flux_correction water_flux_correction Snow temperature is the bulk temperature of the snow, not the surface (skin) temperature. E238 snow_temperature snow_temperature "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. cloud_ice_content_of_atmosphere_layer cloud_ice_content_of_atmosphere_layer vorpot K m2 kg-1 s-1 ertel_potential_vorticity ertel_potential_vorticity cloud_top refers to the top of the highest cloud. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. Convective cloud is that produced by the convection schemes in an atmosphere model. convective_cloud_top_altitude convective_cloud_top_altitude The surface called "surface" means the lower boundary of the atmosphere. "shortwave" means shortwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". Surface downwelling shortwave is the sum of direct and diffuse solar radiation incident on the surface, and is sometimes called "global radiation". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 117 E169 rsds surface_downwelling_shortwave_flux_in_air surface_downwelling_shortwave_flux_in_air "Content" indicates a quantity per unit area. "Litter carbon" is dead inorganic material in or above the soil quantified as the mass of carbon which it contains. litter_carbon_content litter_carbon_content In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. convective_rainfall_flux convective_rainfall_flux "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. Projection coordinates are distances in the x- and y-directions on a plane onto which the surface of the Earth has been projected according to a map projection. The relationship between the projection coordinates and latitude and longitude is described by the grid_mapping. projection_x_coordinate projection_x_coordinate "Eastward" indicates a vector component which is positive when directed eastward (negative westward). "Downward" indicates a vector component which is positive when directed downward (negative upward). "Downward eastward" indicates the ZX component of a tensor. Momentum flux is dimensionally equivalent to stress and pressure. It is a tensor quantity. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 124 downward_eastward_momentum_flux_in_air downward_eastward_momentum_flux_in_air Height is the vertical distance above the surface. zh height height The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. "Bedrock" is the solid Earth surface beneath land ice or ocean water. The zero of bedrock altitude change is arbitrary. Isostatic adjustment is the vertical movement of the lithosphere due to changing surface ice and water loads. bedrock_altitude_change_due_to_isostatic_adjustment bedrock_altitude_change_due_to_isostatic_adjustment The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The surface sensible heat flux, also called "turbulent" heat flux, is the exchange of heat between the surface and the air by motion of air. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downward_sensible_heat_flux surface_downward_sensible_heat_flux "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. E143 lwe_thickness_of_convective_precipitation_amount lwe_thickness_of_convective_precipitation_amount "Amount" means mass per unit area. "Water" means water in all phases. "Canopy" means the plant or vegetation canopy. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) water_evaporation_amount_from_canopy water_evaporation_amount_from_canopy cloud_top refers to the top of the highest cloud. Height is the vertical distance above the surface. Convective cloud is that produced by the convection schemes in an atmosphere model. convective_cloud_top_height convective_cloud_top_height The surface called "surface" means the lower boundary of the atmosphere. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. snm surface_snow_melt_flux surface_snow_melt_flux The ocean mixed layer is the upper part of the ocean, regarded as being well-mixed. The base of the mixed layer defined by temperature, sigma or sigma_theta is the level at which the quantity indicated differs from its surface value by a certain amount. ocean_mixed_layer_thickness_defined_by_sigma_t ocean_mixed_layer_thickness_defined_by_sigma_t "Northward" indicates a vector component which is positive when directed northward (negative southward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. northward_mass_flux_of_air northward_mass_flux_of_air The virtual temperature of air is the temperature at which the dry air constituent of a parcel of moist air would have the same density as the moist air at the same pressure. 12 virtual_temperature virtual_temperature "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) Wind shear is the derivative of wind with respect to height. 45 eastward_wind_shear eastward_wind_shear "lwe" means liquid water equivalent. lwe_snowfall_rate lwe_snowfall_rate "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. dry_energy_content_of_atmosphere_layer dry_energy_content_of_atmosphere_layer The brightness temperature of a body is the temperature of a black body which radiates the same power per unit solid angle per unit area. 118 brightness_temperature brightness_temperature The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_spectral_radiance_in_air_emerging_from_sea_water surface_upwelling_spectral_radiance_in_air_emerging_from_sea_water The scattering angle is that between the direction of the beam of incident radiation and the direction into which it is scattered. rad scattering_angle scattering_angle A variable with the standard name of land_cover contains strings which indicate the nature of the anthropogenic land use or vegetation e.g. urban, grass, needleleaf trees, ice. These strings have not yet been standardised. The alternative standard name of surface_cover is a generalisation of land_cover. Alternatively, the data variable may contain integers which can be translated to strings using flag_values and flag_meanings attributes. land_cover land_cover In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. prc convective_precipitation_flux convective_precipitation_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tnt tendency_of_air_temperature_due_to_diabatic_processes tendency_of_air_temperature_due_to_diabatic_processes "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_temperature land_ice_temperature dbar Solar elevation angle is the angle between the line of sight to the sun and the local horizontal. solar_elevation_angle solar_elevation_angle Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. mass_concentration_of_oxygen_in_sea_water mass_concentration_of_oxygen_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. "magnitude_of_X" means magnitude of a vector X. "Downward" indicates a vector component which is positive when directed downward (negative upward). magnitude_of_surface_downward_stress magnitude_of_surface_downward_stress The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tntlsp tendency_of_air_temperature_due_to_large_scale_precipitation tendency_of_air_temperature_due_to_large_scale_precipitation "Area fraction" means the fraction of horizontal area. To specify which area is quantified by a variable of area_fraction, provide a coordinate variable or scalar coordinate variable of land_cover or surface_cover. Alternatively, if one is defined, use a more specific standard name of "X_area_fraction" for the fraction of horizontal area occupied by X. area_fraction area_fraction The surface called "surface" means the lower boundary of the atmosphere. Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_photosynthetic_radiative_flux_in_air surface_downwelling_photosynthetic_radiative_flux_in_air Sigma-t of sea water is the density of water at atmospheric pressure (i.e. the surface) having the same temperature and salinity, minus 1000 kg m-3. Note that sea water sigma is not the same quantity as the dimensionless ocean sigma coordinate (see Appendix D of the CF convention), for which there is another standard name. sea_water_sigma_t sea_water_sigma_t s-1 m-3 "shortwave" means shortwave radiation. Radiance is the radiative flux in a particular direction, per unit of solid angle. If radiation is isotropic, the radiance is independent of direction, so the direction should not be specified. If the radiation is directionally dependent, a standard name of upwelling or downwelling radiance should be chosen instead. isotropic_shortwave_radiance_in_air isotropic_shortwave_radiance_in_air "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of sigma plays the role of the upward component of air velocity when the atmosphere sigma coordinate (a dimensionless atmosphere vertical coordinate) is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of sigma; downwards is positive. See Appendix D of the CF convention for information about dimensionless vertical coordinates. 38 lagrangian_tendency_of_atmosphere_sigma_coordinate lagrangian_tendency_of_atmosphere_sigma_coordinate Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. freezing_level_altitude freezing_level_altitude The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-optical_thickness) on traversing the path. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). optical_thickness_of_atmosphere_layer_due_to_aerosol optical_thickness_of_atmosphere_layer_due_to_aerosol The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area. Sublimation is the conversion of solid into vapor. surface_snow_sublimation_amount surface_snow_sublimation_amount The forecast reference time in NWP is the "data time", the time of the analysis from which the forecast was made. It is not the time for which the forecast is valid; the standard name of time should be used for that time. forecast_reference_time forecast_reference_time Sea ice freeboard is the height of the sea-ice upper surface above the water surface. sea_ice_freeboard sea_ice_freeboard Net primary productivity is the excess of gross_primary_producivity (rate of synthesis of biomass per unit area from inorganic precursors by autotrophs, or "producers", especially by photosynthesising plants using sunlight for energy) over the rate at which they themselves respire some of this biomass (plant_respiration, assuming all producers to be plants). "Productivity of carbon" refers to the production of biomass expressed as the mass of carbon which it contains. net_primary_productivity_of_carbon net_primary_productivity_of_carbon "lwe" means liquid water equivalent. "moisture" means water in all phases contained in soil. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Quantities defined for a soil layer must have a vertical coordinate variable with boundaries indicating the extent of the layer(s). lwe_thickness_of_moisture_content_of_soil_layer lwe_thickness_of_moisture_content_of_soil_layer The Coriolis parameter is twice the component of the earth's angular velocity about the local vertical i.e. 2 W sin L, where L is latitude and W the angular speed of the earth. coriolis_parameter coriolis_parameter "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. atmosphere_cloud_liquid_water_content atmosphere_cloud_liquid_water_content The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. E211 surface_net_downward_longwave_flux_assuming_clear_sky surface_net_downward_longwave_flux_assuming_clear_sky "anomaly" means difference from climatology. 26 air_pressure_anomaly air_pressure_anomaly See Appendix D of the CF convention for information about dimensionless vertical coordinates. atmosphere_sigma_coordinate atmosphere_sigma_coordinate The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. 97 tendency_of_sea_ice_thickness_due_to_thermodynamics tendency_of_sea_ice_thickness_due_to_thermodynamics Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_precipitation_in_air mass_fraction_of_precipitation_in_air "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. The equivalent pressure of a particular constituent of the atmosphere is the surface pressure exerted by the weight of that constituent alone. equivalent_pressure_of_atmosphere_ozone_content equivalent_pressure_of_atmosphere_ozone_content "square_of_X" means X*X. "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of air pressure, often called "omega", plays the role of the upward component of air velocity when air pressure is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of air pressure; downwards is positive. Pa2 s-2 square_of_lagrangian_tendency_of_air_pressure square_of_lagrangian_tendency_of_air_pressure In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 59 pr precipitation_flux precipitation_flux A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. "toa" means top of atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. toa_net_downward_shortwave_flux_assuming_clear_sky toa_net_downward_shortwave_flux_assuming_clear_sky Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The volume scattering/absorption/attenuation coefficient is the fractional change of radiative flux per unit path length due to the stated process. Coefficients with canonical units of m2 s-1 i.e. multiplied by density have standard names with specific_ instead of volume_. The scattering/absorption/attenuation coefficient is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength is included to specify the wavelength. Attenuation is the sum of absorption and scattering. Attenuation is sometimes called "extinction". Also called "diffuse" attenuation, the attenuation of downwelling radiative flux refers to the decrease with decreasing height or increasing depth of the downwelling component of radiative flux, regardless of incident direction. volume_attenuation_coefficient_of_downwelling_radiative_flux_in_sea_water volume_attenuation_coefficient_of_downwelling_radiative_flux_in_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "change_over_time_in_X" means change in a quantity X over a time-interval, which should be defined by the bounds of the time coordinate. "Content" indicates a quantity per unit area. "Water" means water in all phases. change_over_time_in_atmospheric_water_content_due_to_advection change_over_time_in_atmospheric_water_content_due_to_advection The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. tendency_of_atmosphere_enthalpy_content_due_to_advection tendency_of_atmosphere_enthalpy_content_due_to_advection Downwelling radiation is radiation from above. It does not mean "net downward". A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_spectral_photon_flux_in_sea_water downwelling_spectral_photon_flux_in_sea_water "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. lwe_thickness_of_convective_snowfall_amount lwe_thickness_of_convective_snowfall_amount "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Omnidirectional spherical irradiance is the radiation incident on unit area of a spherical (or "4-pi") collector. It is sometimes called "scalar irradiance". Radiation incident on a 2-pi collector has standard names of "spherical irradiance" which specify up/downwelling. W m-3 omnidirectional_spectral_spherical_irradiance_in_sea_water omnidirectional_spectral_spherical_irradiance_in_sea_water "Amount" means mass per unit area. transpiration_amount transpiration_amount The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). tendency_of_mass_fraction_of_cloud_liquid_water_in_air_due_to_advection tendency_of_mass_fraction_of_cloud_liquid_water_in_air_due_to_advection "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Potential energy is the sum of the gravitational potential energy relative to the geoid and the centripetal potential energy. (The geopotential is the specific potential energy.) atmosphere_potential_energy_content atmosphere_potential_energy_content The visibility is the distance at which something can be seen. 20 visibility_in_air visibility_in_air "product_of_X_and_Y" means X*Y. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpvta K m s-1 product_of_northward_wind_and_air_temperature product_of_northward_wind_and_air_temperature "Northward" indicates a vector component which is positive when directed northward (negative southward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. northward_atmosphere_dry_static_energy_transport_across_unit_distance northward_atmosphere_dry_static_energy_transport_across_unit_distance Runoff is the liquid water which drains from land. If not specified, "runoff" refers to the sum of surface runoff and subsurface drainage. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. subsurface_runoff_flux subsurface_runoff_flux "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. Specific mass balance means the net rate at which ice is added per unit area at the land ice surface. land_ice_surface_specific_mass_balance land_ice_surface_specific_mass_balance The surface called "surface" means the lower boundary of the atmosphere. "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. "Downward" indicates a vector component which is positive when directed downward (negative upward). surface_downward_x_stress surface_downward_x_stress Model level number should be understood as equivalent to layer number. model_level_number_at_top_of_atmosphere_boundary_layer model_level_number_at_top_of_atmosphere_boundary_layer "Northward" indicates a vector component which is positive when directed northward (negative southward). "Downward" indicates a vector component which is positive when directed downward (negative upward). "Downward northward" indicates the ZY component of a tensor. A downward northward stress is a downward flux of northward momentum, which accelerates the lower medium northward and the upper medium southward. downward_northward_stress_at_sea_ice_base downward_northward_stress_at_sea_ice_base Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. platform_yaw_angle platform_yaw_angle The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. "Upward" indicates a vector component which is positive when directed upward (negative downward). The surface water flux is the result of precipitation and evaporation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upward_water_flux surface_upward_water_flux "moisture" means water in all phases contained in soil. "unfrozen_water" means liquid and vapour. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_unfrozen_water_in_soil_moisture mass_fraction_of_unfrozen_water_in_soil_moisture "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. dry_static_energy_content_of_atmosphere_layer dry_static_energy_content_of_atmosphere_layer Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) In meteorological reports, the direction of the wind vector is usually (but not always) given as the direction from which it is blowing (wind_from_direction) (westerly, northerly, etc.). In other contexts, such as atmospheric modelling, it is often natural to give the direction in the usual manner of vectors as the heading or the direction to which it is blowing (wind_to_direction) (eastward, southward, etc.) "to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. wind_to_direction wind_to_direction "square_of_X" means X*X. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpuua square_of_eastward_wind square_of_eastward_wind "Content" indicates a quantity per unit area. The "soil content" of a quantity refers to the vertical integral from the surface down to the bottom of the soil model. For the content between specified levels in the soil, standard names including content_of_soil_layer are used. soil_carbon_content soil_carbon_content cloud_base refers to the base of the lowest cloud. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. Convective cloud is that produced by the convection schemes in an atmosphere model. convective_cloud_base_altitude convective_cloud_base_altitude moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y. moles_of_nitrite_per_unit_mass_in_sea_water moles_of_nitrite_per_unit_mass_in_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Atmosphere_Xward_stress is a stress which tends to accelerate the atmosphere in direction X. tauvgwd atmosphere_northward_stress_due_to_gravity_wave_drag atmosphere_northward_stress_due_to_gravity_wave_drag "X_area" means the horizontal area occupied by X within the grid cell. atmosphere_mass_per_unit_area atmosphere_mass_per_unit_area "longwave" means longwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upwelling_longwave_flux_in_air upwelling_longwave_flux_in_air "moisture" means water in all phases contained in soil. "Content" indicates a quantity per unit area. The "soil content" of a quantity refers to the vertical integral from the surface down to the bottom of the soil model. For the content between specified levels in the soil, standard names including content_of_soil_layer are used. The field capacity of soil is the maximum content of water it can retain against gravitational drainage. mrsofc soil_moisture_content_at_field_capacity soil_moisture_content_at_field_capacity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Potential energy is the sum of the gravitational potential energy relative to the geoid and the centripetal potential energy. (The geopotential is the specific potential energy.) tendency_of_atmosphere_potential_energy_content_due_to_advection tendency_of_atmosphere_potential_energy_content_due_to_advection See Appendix D of the CF convention for information about dimensionless vertical coordinates. Note that the ocean sigma coordinate is not the same quantity as sea water sigma (excess of density over 1000 kg m-3), for which there are various other standard names. ocean_sigma_coordinate ocean_sigma_coordinate snow_density snow_density "condensed_water" means liquid and ice. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. 76 clwvi atmosphere_cloud_condensed_water_content atmosphere_cloud_condensed_water_content A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. "toa" means top of atmosphere. The TOA outgoing shortwave flux is the reflected and scattered solar radiative flux i.e. the "upwelling" TOA shortwave flux, sometimes called the "outgoing shortwave radiation" or "OSR". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsutcs toa_outgoing_shortwave_flux_assuming_clear_sky toa_outgoing_shortwave_flux_assuming_clear_sky "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) y_wind y_wind Realization is used to label a dimension that can be thought of asa statistical sample, e.g., labelling members of a model ensemble. realization realization "Amount" means mass per unit area. Runoff is the liquid water which drains from land. If not specified, "runoff" refers to the sum of surface runoff and subsurface drainage. runoff_amount runoff_amount "frozen_water" means ice. "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. volume_fraction_of_frozen_water_in_soil volume_fraction_of_frozen_water_in_soil tropopause_air_pressure tropopause_air_pressure Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. Photon spherical irradiance is the photon flux incident on unit area of a hemispherical (or "2-pi") collector. A photon flux is specified in terms of numbers of photons expressed in moles. downwelling_photosynthetic_photon_spherical_irradiance_in_sea_water downwelling_photosynthetic_photon_spherical_irradiance_in_sea_water "tendency_of_X" means derivative of X with respect to time. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tnmmutot tendency_of_eastward_wind tendency_of_eastward_wind "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Ocean potential vorticity is the vertically averaged absolute vorticity of a layer of the ocean divided by the thickness of the layer. potential_vorticity_of_ocean_layer potential_vorticity_of_ocean_layer A velocity is a vector quantity. "Horizontal" indicates that the velocity potential applies to a horizontal velocity field on a particular vertical level. 36 atmosphere_horizontal_velocity_potential atmosphere_horizontal_velocity_potential sea_level means mean sea level, which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL. 2 E151 psl air_pressure_at_sea_level air_pressure_at_sea_level cloud_base refers to the base of the lowest cloud. Model level number should be understood as equivalent to layer number. Convective cloud is that produced by the convection schemes in an atmosphere model. model_level_number_at_convective_cloud_base model_level_number_at_convective_cloud_base The surface called "surface" means the lower boundary of the atmosphere. Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. "Upward" indicates a vector component which is positive when directed upward (negative downward). The surface sensible heat flux, also called "turbulent" heat flux, is the exchange of heat between the surface and the air by motion of air. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upward_sensible_heat_flux_where_sea surface_upward_sensible_heat_flux_where_sea Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). In an atmosphere model, stratiform cloud is that produced by large-scale convergence (not the convection schemes). mass_fraction_of_stratiform_cloud_liquid_water_in_air mass_fraction_of_stratiform_cloud_liquid_water_in_air The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upwelling_spectral_radiative_flux_in_sea_water surface_upwelling_spectral_radiative_flux_in_sea_water "lwe" means liquid water equivalent. "moisture" means water in all phases contained in soil. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. "Content" indicates a quantity per unit area. The "soil content" of a quantity refers to the vertical integral from the surface down to the bottom of the soil model. For the content between specified levels in the soil, standard names including content_of_soil_layer are used. E140 lwe_thickness_of_soil_moisture_content lwe_thickness_of_soil_moisture_content Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). trsul mass_concentration_of_sulfate_aerosol_in_air mass_concentration_of_sulfate_aerosol_in_air The surface called "surface" means the lower boundary of the atmosphere. surface_roughness_length_for_momentum_in_air surface_roughness_length_for_momentum_in_air "Amount" means mass per unit area. Runoff is the liquid water which drains from land. If not specified, "runoff" refers to the sum of surface runoff and subsurface drainage. subsurface_runoff_amount subsurface_runoff_amount In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. transpiration_flux transpiration_flux 52 E157 hur relative_humidity relative_humidity "direction_of_X" means direction of a vector, a bearing. A velocity is a vector quantity. Sea ice velocity is defined as a two-dimensional vector, with no vertical component. 93 direction_of_sea_ice_velocity direction_of_sea_ice_velocity Longitude is positive eastward; its units of degree_east (or equivalent) indicate this explicitly. In a latitude-longitude system defined with respect to a rotated North Pole, the standard name of grid_longitude should be used instead of longitude. Grid longitude is positive in the grid-eastward direction, but its units should be plain degree. longitude longitude longitude The ocean mixed layer is the upper part of the ocean, regarded as being well-mixed. The base of the mixed layer defined by the mixing scheme is a diagnostic of ocean models. ocean_mixed_layer_thickness_defined_by_mixing_scheme ocean_mixed_layer_thickness_defined_by_mixing_scheme "product_of_X_and_Y" means X*Y. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. product_of_northward_wind_and_omega product_of_northward_wind_and_omega The surface called "surface" means the lower boundary of the atmosphere. Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_spectral_radiance_in_air surface_upwelling_spectral_radiance_in_air A velocity is a vector quantity. "Radial velocity away from instrument" means the component of the velocity of the scatterers along the line of sight of the instrument where positive implies movement away from the instrument (i.e. outward). The "instrument" (examples are radar and lidar) is the device used to make the observation, and the "scatterers" are what causes the transmitted signal to be returned to the instrument (examples are aerosols, hydrometeors and refractive index irregularities), of whatever kind the instrument detects. radial_velocity_of_scatterers_away_from_instrument radial_velocity_of_scatterers_away_from_instrument "product_of_X_and_Y" means X*Y. "specific" means per unit mass. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. Specific humidity is the mass fraction of water vapor in (moist) air. product_of_air_temperature_and_specific_humidity product_of_air_temperature_and_specific_humidity "Respiration carbon" refers to the rate at which biomass is respired expressed as the mass of carbon which it contains. Plant respiration is the sum of respiration by parts of plants both above and below the soil. Plants which photosynthesise are autotrophs i.e. "producers" of the biomass which they respire from inorganic precursors using sunlight for energy. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. plant_respiration_carbon_flux plant_respiration_carbon_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by the ocean gyre is geometrically defined as being the part due to the vertical integral of the product of deviations of velocity and tracer from their zonal means. The velocity does not include "bolus" or Gent-McWilliams velocity. sltovgyre northward_ocean_salt_transport_due_to_gyre northward_ocean_salt_transport_due_to_gyre "Amount" means mass per unit area. snowfall_amount snowfall_amount "product_of_X_and_Y" means X*Y. "specific" means per unit mass. A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). Specific humidity is the mass fraction of water vapor in (moist) air. Upward air velocity is the vertical component of the 3D air velocity vector. product_of_upward_air_velocity_and_specific_humidity product_of_upward_air_velocity_and_specific_humidity sea_water_pressure sea_water_pressure "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_mass_flux_of_air upward_mass_flux_of_air "tendency_of_X" means derivative of X with respect to time. The Lagrangian tendency of a quantity is its rate of change following the motion of the fluid, also called the "material derivative" or "convective derivative". The Lagrangian tendency of air pressure, often called "omega", plays the role of the upward component of air velocity when air pressure is being used as the vertical coordinate. If the vertical air velocity is upwards, it is negative when expressed as a tendency of air pressure; downwards is positive. 39 E135 wap lagrangian_tendency_of_air_pressure lagrangian_tendency_of_air_pressure "Water" means water in all phases. "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. The field capacity of soil is the maximum content of water it can retain against gravitational drainage. volume_fraction_of_water_in_soil_at_field_capacity volume_fraction_of_water_in_soil_at_field_capacity Latitude is positive northward; its units of degree_north (or equivalent) indicate this explicitly. In a latitude-longitude system defined with respect to a rotated North Pole, the standard name of grid_latitude should be used instead of latitude. Grid latitude is positive in the grid-northward direction, but its units should be plain degree. latitude latitude latitude "lwe" means liquid water equivalent. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. The land ice calving rate is the rate at which ice is lost per unit area through calving into the ocean. land_ice_lwe_calving_rate land_ice_lwe_calving_rate The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_radiative_flux_in_sea_water surface_downwelling_radiative_flux_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. The snow melt heat flux is the supply of latent heat which is melting snow at freezing point. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_snow_melt_heat_flux surface_snow_melt_heat_flux "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. atmosphere_enthalpy_content atmosphere_enthalpy_content The surface called "surface" means the lower boundary of the atmosphere. "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. "Downward" indicates a vector component which is positive when directed downward (negative upward). surface_downward_y_stress surface_downward_y_stress X_binary_mask has 1 where condition X is met, 0 elsewhere. 1 = land, 0 = sea. E172 land_binary_mask land_binary_mask "toa" means top of atmosphere. Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.). toa_instantaneous_radiative_forcing toa_instantaneous_radiative_forcing "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. sftgif land_ice_area_fraction land_ice_area_fraction A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). barotropic_northward_sea_water_velocity barotropic_northward_sea_water_velocity Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. surface_temperature_where_land surface_temperature_where_land The surface called "surface" means the lower boundary of the atmosphere. "longwave" means longwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rlds surface_downwelling_longwave_flux_in_air surface_downwelling_longwave_flux_in_air Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The volume scattering/absorption/attenuation coefficient is the fractional change of radiative flux per unit path length due to the stated process. Coefficients with canonical units of m2 s-1 i.e. multiplied by density have standard names with specific_ instead of volume_. The scattering/absorption/attenuation coefficient is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength is included to specify the wavelength. volume_absorption_coefficient_of_radiative_flux_in_sea_water volume_absorption_coefficient_of_radiative_flux_in_sea_water Humidity mixing ratio of a parcel of moist air is the ratio of the mass of water vapor to the mass of dry air. 53 humidity_mixing_ratio humidity_mixing_ratio Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 126 wind_mixing_energy_flux_into_ocean wind_mixing_energy_flux_into_ocean The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. tendency_of_atmosphere_water_vapor_content_due_to_shallow_convection tendency_of_atmosphere_water_vapor_content_due_to_shallow_convection "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". In an atmosphere model, stratiform cloud is that produced by large-scale convergence (not the convection schemes). stratiform_cloud_area_fraction_in_atmosphere_layer stratiform_cloud_area_fraction_in_atmosphere_layer A period is an interval of time, or the time-period of an oscillation. The zero upcrossing period is defined as the time interval between consecutive occasions on which the surface height passes upward above the mean level. Swell waves are waves on the ocean surface. sea_surface_swell_wave_zero_upcrossing_period sea_surface_swell_wave_zero_upcrossing_period cloud_base refers to the base of the lowest cloud. air_pressure_at_cloud_base air_pressure_at_cloud_base Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The volume scattering/absorption/attenuation coefficient is the fractional change of radiative flux per unit path length due to the stated process. Coefficients with canonical units of m2 s-1 i.e. multiplied by density have standard names with specific_ instead of volume_. The scattering/absorption/attenuation coefficient is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength is included to specify the wavelength. Attenuation is the sum of absorption and scattering. Attenuation is sometimes called "extinction". Beam attenuation refers to the decrease of radiative flux along the direction of the incident path. It is distinguished from attenuation of the downwelling component of radiative flux from any incident direction, also called "diffuse" attenuation. volume_beam_attenuation_coefficient_of_radiative_flux_in_sea_water volume_beam_attenuation_coefficient_of_radiative_flux_in_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). tendency_of_mass_fraction_of_cloud_ice_in_air_due_to_advection tendency_of_mass_fraction_of_cloud_ice_in_air_due_to_advection The ocean meridional overturning streamfunction should not include not include "bolus" or Gent-McWilliams velocity. stfmmcgo m3 s-1 ocean_meridional_overturning_streamfunction ocean_meridional_overturning_streamfunction "Amount" means mass per unit area. 62 large_scale_precipitation_amount large_scale_precipitation_amount "Amount" means mass per unit area. The construction thickness_of_[X_]snowfall_amount means the accumulated "depth" of snow which fell i.e. the thickness of the layer of snow at its own density. There are corresponding standard names for liquid water equivalent (lwe) thickness. thickness_of_large_scale_snowfall_amount thickness_of_large_scale_snowfall_amount "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. lwe_thickness_of_precipitation_amount lwe_thickness_of_precipitation_amount "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. The land ice basal melt rate is the rate at which ice is lost per unit area at the base of the ice. land_ice_basal_melt_rate land_ice_basal_melt_rate "longwave" means longwave radiation. Net absorbed radiation is the difference between absorbed and emitted radiation. atmosphere_net_rate_of_absorption_of_longwave_energy atmosphere_net_rate_of_absorption_of_longwave_energy wet_bulb_temperature wet_bulb_temperature "longwave" means longwave radiation. Adjusted forcing is the radiative flux change caused by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.) after allowance for stratospheric temperature adjustment. tropopause_adjusted_longwave_forcing tropopause_adjusted_longwave_forcing See Appendix D of the CF convention for information about dimensionless vertical coordinates. atmosphere_hybrid_height_coordinate atmosphere_hybrid_height_coordinate The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tntdc tendency_of_air_temperature_due_to_dry_convection tendency_of_air_temperature_due_to_dry_convection Downwelling radiation is radiation from above. It does not mean "net downward". Spherical irradiance is the radiation incident on unit area of a hemispherical (or "2-pi") collector. It is sometimes called "scalar irradiance". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of "omnidirectional spherical irradiance". downwelling_spherical_irradiance_in_sea_water downwelling_spherical_irradiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. Upwelling radiation is radiation from below. It does not mean "net upward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_radiance_in_air surface_upwelling_radiance_in_air The surface called "surface" means the lower boundary of the atmosphere. "longwave" means longwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rls surface_net_downward_longwave_flux surface_net_downward_longwave_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. tendency_of_atmosphere_water_vapor_content_due_to_convection tendency_of_atmosphere_water_vapor_content_due_to_convection The geoid is a surface of constant geopotential with which mean sea level would coincide if the ocean were at rest. (The volume enclosed between the geoid and the sea floor equals the mean volume of water in the ocean.) In an ocean GCM the geoid is the surface of zero depth, or the rigid lid if the model uses that approximation. "Sea surface height" is a time-varying quantity. By definition of the geoid, the global average of the time-mean sea surface height (i.e. mean sea level) above the geoid must be zero. The standard name for the height of the sea surface above mean sea level is sea_surface_height_above_sea_level. sea_surface_height_above_geoid sea_surface_height_above_geoid "Amount" means mass per unit area. The construction thickness_of_[X_]rainfall_amount means the accumulated "depth" of rainfall i.e. the thickness of a layer of liquid water having the same mass per unit area as the rainfall amount. thickness_of_rainfall_amount thickness_of_rainfall_amount A period is an interval of time, or the time-period of an oscillation. Wind waves are waves on the ocean surface. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) 103 sea_surface_wind_wave_period sea_surface_wind_wave_period Frequency is the number of oscillations of a wave per unit time. sea_surface_wave_frequency sea_surface_wave_frequency "Amount" means mass per unit area. "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) Potential evaporation is the rate at which evaporation would take place under unaltered ambient conditions (temperature, relative humidity, wind, etc.) if the supply of water were unlimited, as if from an open water surface. water_potential_evaporation_amount water_potential_evaporation_amount "anomaly" means difference from climatology. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. 25 air_temperature_anomaly air_temperature_anomaly Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_dimethyl_sulfide_in_air mass_fraction_of_dimethyl_sulfide_in_air The surface called "surface" means the lower boundary of the atmosphere. "Northward" indicates a vector component which is positive when directed northward (negative southward). "Downward" indicates a vector component which is positive when directed downward (negative upward). "Downward northward" indicates the ZY component of a tensor. A downward northward stress is a downward flux of northward momentum, which accelerates the lower medium northward and the upper medium southward. The surface downward stress is the windstress on the surface. E181 tauv surface_downward_northward_stress surface_downward_northward_stress "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". The cloud area fraction is for the whole atmosphere column, as seen from the surface or the top of the atmosphere. The cloud area fraction in a layer of the atmosphere has the standard name cloud_area_fraction_in_atmosphere_layer. Convective cloud is that produced by the convection schemes in an atmosphere model. 72 E185 convective_cloud_area_fraction convective_cloud_area_fraction "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. "Atmosphere energy content" has not yet been precisely defined! Please express your views on this quantity on the CF email list. atmosphere_energy_content atmosphere_energy_content "shortwave" means shortwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. downwelling_shortwave_radiance_in_air downwelling_shortwave_radiance_in_air height_above_sea_floor height_above_sea_floor A velocity is a vector quantity. "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_x_velocity land_ice_x_velocity "tendency_of_X" means derivative of X with respect to time. "X_area" means the horizontal area occupied by X within the grid cell. tendency_of_atmosphere_mass_per_unit_area tendency_of_atmosphere_mass_per_unit_area The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". Surface downwelling shortwave is the sum of direct and diffuse solar radiation incident on the surface, and is sometimes called "global radiation". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsdscs surface_downwelling_shortwave_flux_in_air_assuming_clear_sky surface_downwelling_shortwave_flux_in_air_assuming_clear_sky "tendency_of_X" means derivative of X with respect to time. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. tendency_of_specific_humidity tendency_of_specific_humidity The surface called "surface" means the lower boundary of the atmosphere. Upwelling radiation is radiation from below. It does not mean "net upward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upwelling_photosynthetic_photon_flux_in_air surface_upwelling_photosynthetic_photon_flux_in_air "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. E144 lwe_thickness_of_snowfall_amount lwe_thickness_of_snowfall_amount "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. tendency_of_dry_energy_content_of_atmosphere_layer tendency_of_dry_energy_content_of_atmosphere_layer Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. platform_pitch_rate platform_pitch_rate K2 "Eastward" indicates a vector component which is positive when directed eastward (negative westward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. eastward_mass_flux_of_air eastward_mass_flux_of_air "Northward" indicates a vector component which is positive when directed northward (negative southward). Ocean transport means transport by all processes, both sea water and sea ice. northward_ocean_freshwater_transport northward_ocean_freshwater_transport Global average thermosteric sea level change is the part caused by change in density due to change in temperature i.e. thermal expansion. Zero sea level change is an arbitrary level. global_average_thermosteric_sea_level_change global_average_thermosteric_sea_level_change 80 to sea_water_temperature sea_water_temperature The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. Spherical irradiance is the radiation incident on unit area of a hemispherical (or "2-pi") collector. It is sometimes called "scalar irradiance". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of "omnidirectional spherical irradiance". surface_downwelling_photosynthetic_spherical_irradiance_in_sea_water surface_downwelling_photosynthetic_spherical_irradiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upwelling_longwave_flux_in_air_assuming_clear_sky surface_upwelling_longwave_flux_in_air_assuming_clear_sky "longwave" means longwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_longwave_flux_in_air downwelling_longwave_flux_in_air K s The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. E210 surface_net_downward_shortwave_flux_assuming_clear_sky surface_net_downward_shortwave_flux_assuming_clear_sky "Northward" indicates a vector component which is positive when directed northward (negative southward). Momentum flux is dimensionally equivalent to stress and pressure. It is a tensor quantity. Flux correction is also called "flux adjustment". A positive flux correction is downward i.e. added to the ocean. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. tauvcorr northward_momentum_flux_correction northward_momentum_flux_correction The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Photon spherical irradiance is the photon flux incident on unit area of a hemispherical (or "2-pi") collector. A photon flux is specified in terms of numbers of photons expressed in moles. surface_downwelling_spectral_photon_spherical_irradiance_in_sea_water surface_downwelling_spectral_photon_spherical_irradiance_in_sea_water "lwe" means liquid water equivalent. lwe_convective_precipitation_rate lwe_convective_precipitation_rate "product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). product_of_eastward_sea_water_velocity_and_temperature product_of_eastward_sea_water_velocity_and_temperature "lwe" means liquid water equivalent. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. The land ice basal melt rate is the rate at which ice is lost per unit area at the base of the ice. land_ice_lwe_basal_melt_rate land_ice_lwe_basal_melt_rate The atmosphere boundary layer thickness is the "depth" or "height" of the (atmosphere) planetary boundary layer. zmla atmosphere_boundary_layer_thickness atmosphere_boundary_layer_thickness "frozen_water" means ice. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Quantities defined for a soil layer must have a vertical coordinate variable with boundaries indicating the extent of the layer(s). frozen_water_content_of_soil_layer frozen_water_content_of_soil_layer The surface called "surface" means the lower boundary of the atmosphere. The fraction of horizontal area where the surface specified by the axes other than horizontal axes, for instance an isobaric surface, is below the (ground or sea) surface. psbg area_fraction_below_surface area_fraction_below_surface "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. tendency_of_water_vapor_content_of_atmosphere_layer tendency_of_water_vapor_content_of_atmosphere_layer Sigma-theta of sea water is the potential density (i.e. the density when moved adiabatically to a reference pressure) of water having the same temperature and salinity, minus 1000 kg m-3. Note that sea water sigma is not the same quantity as the dimensionless ocean sigma coordinate (see Appendix D of the CF convention), for which there is another standard name. sea_water_sigma_theta sea_water_sigma_theta "moisture" means water in all phases contained in soil. "Content" indicates a quantity per unit area. The "soil content" of a quantity refers to the vertical integral from the surface down to the bottom of the soil model. For the content between specified levels in the soil, standard names including content_of_soil_layer are used. 86 mrso soil_moisture_content soil_moisture_content The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. The partial pressure of a dissolved gas in sea water is the partial pressure in air with which it would be in equilibrium. The partial pressure of a gaseous constituent of air is the pressure which it alone would exert with unchanged temperature and number of moles per unit volume. surface_partial_pressure_of_carbon_dioxide_in_sea_water surface_partial_pressure_of_carbon_dioxide_in_sea_water "integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature deficit is the air temperature threshold minus the air temperature. Its integral with respect to time is often called after its units of "degree-days". integral_of_air_temperature_deficit_wrt_time integral_of_air_temperature_deficit_wrt_time The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. Photon spherical irradiance is the photon flux incident on unit area of a hemispherical (or "2-pi") collector. A photon flux is specified in terms of numbers of photons expressed in moles. surface_downwelling_photosynthetic_photon_spherical_irradiance_in_sea_water surface_downwelling_photosynthetic_photon_spherical_irradiance_in_sea_water "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. E142 lwe_thickness_of_large_scale_precipitation_amount lwe_thickness_of_large_scale_precipitation_amount "wrt" means with respect to. Speed is the magnitude of velocity. Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. The platform speed with respect to air is often called the "air speed" of the platform. platform_speed_wrt_air platform_speed_wrt_air The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by the ocean gyre is geometrically defined as being the part due to the vertical integral of the product of deviations of velocity and tracer from their zonal means. The velocity does not include "bolus" or Gent-McWilliams velocity. htovgyre northward_ocean_heat_transport_due_to_gyre northward_ocean_heat_transport_due_to_gyre Potential temperature is the temperature a parcel of air or sea water would have if moved adiabatically to sea level pressure. sea_water_potential_temperature sea_water_potential_temperature "Eastward" indicates a vector component which is positive when directed eastward (negative westward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. eastward_water_vapor_flux eastward_water_vapor_flux "frozen_water" means ice. "lwe" means liquid water equivalent. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Quantities defined for a soil layer must have a vertical coordinate variable with boundaries indicating the extent of the layer(s). lwe_thickness_of_frozen_water_content_of_soil_layer lwe_thickness_of_frozen_water_content_of_soil_layer Downwelling radiation is radiation from above. It does not mean "net downward". Photon radiance is the photon flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. A photon flux is specified in terms of numbers of photons expressed in moles. downwelling_photon_radiance_in_sea_water downwelling_photon_radiance_in_sea_water "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) E182 lwe_thickness_of_water_evaporation_amount lwe_thickness_of_water_evaporation_amount Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. The platform orientation is the direction in which the "front" or longitudinal axis of the platform is pointing (not necessarily the same as the direction in which it is travelling, called platform_course). platform_orientation platform_orientation "longwave" means longwave radiation. Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.). tropopause_instantaneous_longwave_forcing tropopause_instantaneous_longwave_forcing air_density air_density The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_photon_flux_in_sea_water surface_downwelling_photon_flux_in_sea_water "[horizontal_]divergence_of_X" means [horizontal] divergence of a vector X; if X does not have a vertical component then "horizontal" should be omitted. A velocity is a vector quantity. Sea ice velocity is defined as a two-dimensional vector, with no vertical component. 98 divergence_of_sea_ice_velocity divergence_of_sea_ice_velocity "probability_of_X" means the chance that X is true or of at least one occurrence of X. Space and time coordinates must be used to indicate the area and time-interval to which a probability applies. 60 thunderstorm_probability thunderstorm_probability The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. tendency_of_enthalpy_content_of_atmosphere_layer_due_to_advection tendency_of_enthalpy_content_of_atmosphere_layer_due_to_advection K m-1 The surface called "surface" means the lower boundary of the atmosphere. The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. E139 ts surface_temperature surface_temperature The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_downwelling_spectral_radiance_in_sea_water surface_downwelling_spectral_radiance_in_sea_water "square_of_X" means X*X. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. It is numerically similar to the altitude (or geometric height) and not to the quantity with standard name height, which is relative to the surface. square_of_geopotential_height square_of_geopotential_height The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by diffusion means the part due to horizontal or isopyncal diffusion schemes in an ocean model, but not including the "bolus" or Gent-McWilliams velocity. sltovdiff northward_ocean_salt_transport_due_to_diffusion northward_ocean_salt_transport_due_to_diffusion The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tendency_of_air_temperature_due_to_diffusion tendency_of_air_temperature_due_to_diffusion Depth is the vertical distance below the surface. The root depth is maximum depth of soil reached by plant roots, from which they can extract moisture. root_depth root_depth "from_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. sea_surface_wave_from_direction sea_surface_wave_from_direction Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. The platform course is the direction in which the platform is travelling (not necessarily the same as the direction in which it is pointing, called platform_orientation). platform_course platform_course cloud_top refers to the top of the highest cloud. air_pressure_at_cloud_top air_pressure_at_cloud_top The ocean mixed layer is the upper part of the ocean, regarded as being well-mixed. Various criteria are used to define the mixed layer; this can be specified by using a standard name of ocean_mixed_layer_defined_byX. 67 ocean_mixed_layer_thickness ocean_mixed_layer_thickness The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "X_area" means the horizontal area occupied by X within the grid cell. tendency_of_atmosphere_mass_per_unit_area_due_to_advection tendency_of_atmosphere_mass_per_unit_area_due_to_advection The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tnmmuc tendency_of_eastward_wind_due_to_convection tendency_of_eastward_wind_due_to_convection Zenith angle is the angle to the local vertical; a value of zero is directly overhead. zenith_angle zenith_angle The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by bolus advection in an ocean model means the part due to a scheme representing eddy-induced effects not included in the velocity field. northward_ocean_freshwater_transport_due_to_bolus_advection northward_ocean_freshwater_transport_due_to_bolus_advection In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 64 prsn snowfall_flux snowfall_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). tendency_of_mass_fraction_of_cloud_liquid_water_in_air_due_to_diffusion tendency_of_mass_fraction_of_cloud_liquid_water_in_air_due_to_diffusion Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_graupel_in_air mass_fraction_of_graupel_in_air The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "tendency_of_X" means derivative of X with respect to time. "shortwave" means shortwave radiation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tendency_of_air_temperature_due_to_shortwave_heating_assuming_clear_sky tendency_of_air_temperature_due_to_shortwave_heating_assuming_clear_sky The ocean mixed layer is the upper part of the ocean, regarded as being well-mixed. The base of the mixed layer defined by temperature, sigma or sigma_theta is the level at which the quantity indicated differs from its surface value by a certain amount. ocean_mixed_layer_thickness_defined_by_sigma_theta ocean_mixed_layer_thickness_defined_by_sigma_theta "Eastward" indicates a vector component which is positive when directed eastward (negative westward). "Downward" indicates a vector component which is positive when directed downward (negative upward). "Downward eastward" indicates the ZX component of a tensor. A downward eastward stress is a downward flux of eastward momentum, which accelerates the lower medium eastward and the upper medium westward. downward_eastward_stress_at_sea_ice_base downward_eastward_stress_at_sea_ice_base "Northward" indicates a vector component which is positive when directed northward (negative southward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. kg m-1 s-1 northward_atmosphere_water_vapor_transport_across_unit_distance northward_atmosphere_water_vapor_transport_across_unit_distance Flux correction is also called "flux adjustment". A positive flux correction is downward i.e. added to the ocean. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. hfcorr heat_flux_correction heat_flux_correction The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by the ocean gyre is geometrically defined as being the part due to the vertical integral of the product of deviations of velocity and tracer from their zonal means. The velocity does not include "bolus" or Gent-McWilliams velocity. northward_ocean_freshwater_transport_due_to_gyre northward_ocean_freshwater_transport_due_to_gyre The surface called "surface" means the lower boundary of the atmosphere. The partial pressure of a gaseous constituent of air is the pressure which it alone would exert with unchanged temperature and number of moles per unit volume. surface_partial_pressure_of_carbon_dioxide_in_air surface_partial_pressure_of_carbon_dioxide_in_air The surface called "surface" means the lower boundary of the atmosphere. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. surface_specific_humidity surface_specific_humidity "product_of_X_and_Y" means X*Y. "specific" means per unit mass. "Northward" indicates a vector component which is positive when directed northward (negative southward). Specific humidity is the mass fraction of water vapor in (moist) air. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpvhusa product_of_northward_wind_and_specific_humidity product_of_northward_wind_and_specific_humidity "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Momentum flux is dimensionally equivalent to stress and pressure. It is a tensor quantity. Flux correction is also called "flux adjustment". A positive flux correction is downward i.e. added to the ocean. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. tauucorr eastward_momentum_flux_correction eastward_momentum_flux_correction "Respiration carbon" refers to the rate at which biomass is respired expressed as the mass of carbon which it contains. Heterotrophic respiration is respiration by heterotrophs ("consumers"), which are organisms (including animals and decomposers) that consume other organisms or dead organic material, rather than synthesising organic material from inorganic precursors using energy from the environment (especially sunlight) as autotrophs ("producers") do. Heterotrophic respiration goes on both above and within the soil. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. heterotrophic_respiration_carbon_flux heterotrophic_respiration_carbon_flux cloud_top refers to the top of the highest cloud. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. cloud_top_altitude cloud_top_altitude "tendency_of_X" means derivative of X with respect to time. 3 tendency_of_air_pressure tendency_of_air_pressure The surface called "surface" means the lower boundary of the atmosphere. A variable with the standard name of surface_cover contains strings which indicate the nature of the surface e.g. urban, forest, vegetation, land, sea_ice, open_sea. These strings have not yet been standardised. This standard name is a generalisation of land_cover. surface_cover surface_cover "specific" means per unit mass. Potential energy is the sum of the gravitational potential energy relative to the geoid and the centripetal potential energy. (The geopotential is the specific potential energy.) specific_gravitational_potential_energy specific_gravitational_potential_energy "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. kinetic_energy_content_of_atmosphere_layer kinetic_energy_content_of_atmosphere_layer "integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Depth is the vertical distance below the surface. K m integral_of_sea_water_temperature_wrt_depth_in_ocean_layer integral_of_sea_water_temperature_wrt_depth_in_ocean_layer Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_photosynthetic_radiative_flux_in_sea_water downwelling_photosynthetic_radiative_flux_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. surface_geopotential surface_geopotential cloud_top refers to the top of the highest cloud. Model level number should be understood as equivalent to layer number. Convective cloud is that produced by the convection schemes in an atmosphere model. model_level_number_at_convective_cloud_top model_level_number_at_convective_cloud_top "Water" means water in all phases. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. kg s-1 m-1 eastward_atmosphere_water_transport_across_unit_distance eastward_atmosphere_water_transport_across_unit_distance Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. It is numerically similar to the altitude (or geometric height) and not to the quantity with standard name height, which is relative to the surface. 7 E156 zg geopotential_height geopotential_height sea_ice_extent sea_ice_extent "shortwave" means shortwave radiation. Net absorbed radiation is the difference between absorbed and emitted radiation. atmosphere_net_rate_of_absorption_of_shortwave_energy atmosphere_net_rate_of_absorption_of_shortwave_energy Transport across_line means that which crosses a particular line on the Earth's surface; formally this means the integral along the line of the normal component of the transport. sea_ice_transport_across_line sea_ice_transport_across_line concentration_of_chlorophyll_in_sea_water concentration_of_chlorophyll_in_sea_water Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. platform_roll_rate platform_roll_rate "shortwave" means shortwave radiation. "toa" means top of atmosphere. Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.). toa_instantaneous_shortwave_forcing toa_instantaneous_shortwave_forcing A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). 49 eastward_sea_water_velocity eastward_sea_water_velocity "moisture" means water in all phases contained in soil. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Quantities defined for a soil layer must have a vertical coordinate variable with boundaries indicating the extent of the layer(s). mrsos moisture_content_of_soil_layer moisture_content_of_soil_layer In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. large_scale_snowfall_flux large_scale_snowfall_flux moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y. moles_of_nitrate_per_unit_mass_in_sea_water moles_of_nitrate_per_unit_mass_in_sea_water A velocity is a vector quantity. "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. sea_water_y_velocity sea_water_y_velocity "Amount" means mass per unit area. 79 large_scale_snowfall_amount large_scale_snowfall_amount The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. tendency_of_kinetic_energy_content_of_atmosphere_layer_due_to_advection tendency_of_kinetic_energy_content_of_atmosphere_layer_due_to_advection moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y. moles_of_nitrate_and_nitrite_per_unit_mass_in_sea_water moles_of_nitrate_and_nitrite_per_unit_mass_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area. Surface amount refers to the amount on the ground, excluding that on the plant or vegetation canopy. 65 snw surface_snow_amount surface_snow_amount kg "square_of_X" means X*X. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. mptta square_of_air_temperature square_of_air_temperature "Litter carbon" is dead inorganic material in or above the soil quantified as the mass of carbon which it contains. The litter carbon flux is the rate of production of litter. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. litter_carbon_flux litter_carbon_flux "Water" means water in all phases. The water flux into the ocean is the freshwater entering the sea water as a result of precipitation, evaporation, river inflow, sea ice effects and water flux correction (if applied). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. wfo water_flux_into_ocean water_flux_into_ocean The surface called "surface" means the lower boundary of the atmosphere. Sublimation is the conversion of solid into vapor. The snow sublimation heat flux is the supply of latent heat which is causing evaporation of snow to water vapor. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_snow_sublimation_heat_flux surface_snow_sublimation_heat_flux Temperature_of_sensor_for_oxygen_in_sea_water is the instrument temperature used in calculating the concentration of oxygen in sea water; it is not a measurement of the ambient water temperature. temperature_of_sensor_for_oxygen_in_sea_water temperature_of_sensor_for_oxygen_in_sea_water "tendency_of_X" means derivative of X with respect to time. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. "Bedrock" is the solid Earth surface beneath land ice or ocean water. tendency_of_bedrock_altitude tendency_of_bedrock_altitude Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_ozone_in_air mass_fraction_of_ozone_in_air Relative vorticity is the upward component of the vorticity vector i.e. the component which arises from horizontal velocity. 43 E138 atmosphere_relative_vorticity atmosphere_relative_vorticity Absolute vorticity is the sum of relative vorticity and the upward component of vorticity due to the Earth's rotation. 41 atmosphere_absolute_vorticity atmosphere_absolute_vorticity "Content" indicates a quantity per unit area. Thermal energy is the total vibrational energy, kinetic and potential, of all the molecules and atoms in a substance. snow_thermal_energy_content snow_thermal_energy_content freezing_temperature_of_sea_water freezing_temperature_of_sea_water A velocity is a vector quantity. "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_basal_x_velocity land_ice_basal_x_velocity The surface called "surface" means the lower boundary of the atmosphere. 83 E173 surface_roughness_length surface_roughness_length ground_level means the land surface (beneath the snow and surface water, if any). "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_heat_flux_at_ground_level_in_snow downward_heat_flux_at_ground_level_in_snow E145 dissipation_in_atmosphere_boundary_layer dissipation_in_atmosphere_boundary_layer sea_level means mean sea level, which is close to the geoid in sea areas. sea_floor_depth_below_sea_level sea_floor_depth_below_sea_level "lwe" means liquid water equivalent. "Amount" means mass per unit area. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. "Water" means water in all phases, including frozen i.e. ice and snow. "Canopy" means the plant or vegetation canopy. The canopy water is the water on the canopy. lwe_thickness_of_canopy_water_amount lwe_thickness_of_canopy_water_amount Speed is the magnitude of velocity. speed_of_sound_in_air speed_of_sound_in_air bioluminescent_photon_rate_in_sea_water bioluminescent_photon_rate_in_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. tnmrd tendency_of_specific_humidity_due_to_model_physics tendency_of_specific_humidity_due_to_model_physics "lwe" means liquid water equivalent. lwe_large_scale_precipitation_rate lwe_large_scale_precipitation_rate "lwe" means liquid water equivalent. lwe_convective_snowfall_rate lwe_convective_snowfall_rate "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) x_wind x_wind "longwave" means longwave radiation. "toa" means top of atmosphere. Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.). toa_instantaneous_longwave_forcing toa_instantaneous_longwave_forcing "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "Water" means water in all phases. water_content_of_atmosphere_layer water_content_of_atmosphere_layer stfbaro ocean_barotropic_streamfunction ocean_barotropic_streamfunction Global average sea level change is due to change in volume of the water in the ocean, caused by mass and/or density change, or to change in the volume of the ocean basins, caused by tectonics etc. It is sometimes called "eustatic", which is a term that also has other definitions. It differs from the change in the global average sea surface height relative to the centre of the Earth by the global average vertical movement of the ocean floor. Zero sea level change is an arbitrary level. global_average_sea_level_change global_average_sea_level_change "tendency_of_X" means derivative of X with respect to time. tendency_of_ocean_barotropic_streamfunction tendency_of_ocean_barotropic_streamfunction Dew point depression is also called dew point deficit. It is the amount by which the air temperature exceeds its dew point temperature. Dew point temperature is the temperature at which a parcel of air reaches saturation upon being cooled at constant pressure and specific humidity. 18 dew_point_depression dew_point_depression cloud_top refers to the top of the highest cloud. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. air_temperature_at_cloud_top air_temperature_at_cloud_top Frequency is the number of oscillations of a wave per unit time. sound_frequency sound_frequency "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. "Water" means water in all phases. atmosphere_water_content atmosphere_water_content A velocity is a vector quantity. "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. sea_water_x_velocity sea_water_x_velocity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tntmc tendency_of_air_temperature_due_to_moist_convection tendency_of_air_temperature_due_to_moist_convection S m-1 sea_water_electrical_conductivity sea_water_electrical_conductivity "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. If radiation is isotropic, the radiance is independent of direction, so the direction should not be specified. If the radiation is directionally dependent, a standard name of upwelling or downwelling radiance should be chosen instead. isotropic_spectral_radiance_in_air isotropic_spectral_radiance_in_air The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Photon radiance is the photon flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. A photon flux is specified in terms of numbers of photons expressed in moles. surface_downwelling_photosynthetic_photon_radiance_in_sea_water surface_downwelling_photosynthetic_photon_radiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. 84 E174 surface_albedo surface_albedo The surface called "surface" means the lower boundary of the atmosphere. Runoff is the liquid water which drains from land. If not specified, "runoff" refers to the sum of surface runoff and subsurface drainage. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. mrros surface_runoff_flux surface_runoff_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. tendency_of_atmosphere_water_vapor_content_due_to_deep_convection tendency_of_atmosphere_water_vapor_content_due_to_deep_convection Height is the vertical distance above the surface. Wind waves are waves on the ocean surface. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) 102 sea_surface_wind_wave_significant_height sea_surface_wind_wave_significant_height A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). baroclinic_eastward_sea_water_velocity baroclinic_eastward_sea_water_velocity "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. atmosphere_dry_static_energy_content atmosphere_dry_static_energy_content "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Cloud area fraction is also called "cloud amount" and "cloud cover". The cloud area fraction is for the whole atmosphere column, as seen from the surface or the top of the atmosphere. The cloud area fraction in a layer of the atmosphere has the standard name cloud_area_fraction_in_atmosphere_layer. large_scale_cloud_area_fraction large_scale_cloud_area_fraction "specific" means per unit mass. Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. specific_dry_energy_of_air specific_dry_energy_of_air "shortwave" means shortwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. tropopause_upwelling_shortwave_flux tropopause_upwelling_shortwave_flux "product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). The unit of salinity is PSU, which is dimensionless. The units attribute should be given as 1e-3 or 0.001 i.e. parts per thousand if salinity is in PSU. product_of_eastward_sea_water_velocity_and_salinity product_of_eastward_sea_water_velocity_and_salinity Air temperature is the bulk temperature of the air, not the surface (skin) temperature. 11 E130 ta air_temperature air_temperature "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. tendency_of_atmosphere_water_vapor_content tendency_of_atmosphere_water_vapor_content The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-optical_thickness) on traversing the path. The atmosphere optical thickness applies to radiation passing through the entire atmosphere. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). atmosphere_optical_thickness_due_to_aerosol atmosphere_optical_thickness_due_to_aerosol "X_volume_fraction" means the fraction of volume occupied by X. ocean_volume_fraction ocean_volume_fraction Thermal capacity, or heat capacity, is the amount of heat energy required to increase the temperature of 1 kg of material by 1 K. It is a property of the material. soil_thermal_capacity soil_thermal_capacity "frozen_water" means ice. "moisture" means water in all phases contained in soil. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_frozen_water_in_soil_moisture mass_fraction_of_frozen_water_in_soil_moisture "Horizontal" indicates that the streamfunction applies to a horizontal velocity field on a particular vertical level. 35 atmosphere_horizontal_streamfunction atmosphere_horizontal_streamfunction In some atmosphere models, the difference of air pressure from model reference is a prognostic variable, instead of the air pressure itself. The model reference air pressure is a model-dependent constant. difference_of_air_pressure_from_model_reference difference_of_air_pressure_from_model_reference "square_of_X" means X*X. A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). Upward air velocity is the vertical component of the 3D air velocity vector. square_of_upward_air_velocity square_of_upward_air_velocity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tendency_of_northward_wind_due_to_advection tendency_of_northward_wind_due_to_advection The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. tendency_of_atmosphere_kinetic_energy_content_due_to_advection tendency_of_atmosphere_kinetic_energy_content_due_to_advection A velocity is a vector quantity. "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. land_ice_basal_y_velocity land_ice_basal_y_velocity Depth is the vertical distance below the surface. depth depth The surface called "surface" means the lower boundary of the atmosphere. Sublimation is the conversion of solid into vapor. The snow melt and sublimation heat flux is the supply of latent heat which converting snow to liquid water (melting) and water vapor (sublimation). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_snow_melt_and_sublimation_heat_flux surface_snow_melt_and_sublimation_heat_flux "longwave" means longwave radiation. "toa" means top of atmosphere. The TOA outgoing longwave flux is the upwelling thermal radiative flux, often called the "outgoing longwave radiation" or "OLR". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 114 E179 rlut toa_outgoing_longwave_flux toa_outgoing_longwave_flux "Water" means water in all phases. "Canopy" means the plant or vegetation canopy. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_evaporation_flux_from_canopy water_evaporation_flux_from_canopy A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). upward_sea_water_velocity upward_sea_water_velocity "shortwave" means shortwave radiation. "toa" means top of atmosphere. The TOA outgoing shortwave flux is the reflected and scattered solar radiative flux i.e. the "upwelling" TOA shortwave flux, sometimes called the "outgoing shortwave radiation" or "OSR". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsut toa_outgoing_shortwave_flux toa_outgoing_shortwave_flux "anomaly" means difference from climatology. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. It is numerically similar to the altitude (or geometric height) and not to the quantity with standard name height, which is relative to the surface. 27 geopotential_height_anomaly geopotential_height_anomaly A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). barotropic_eastward_sea_water_velocity barotropic_eastward_sea_water_velocity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Speed is the magnitude of velocity. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) The wind speed is the magnitude of the wind velocity. tendency_of_wind_speed_due_to_gravity_wave_drag tendency_of_wind_speed_due_to_gravity_wave_drag The unit of salinity is PSU, which is dimensionless. The units attribute should be given as 1e-3 or 0.001 i.e. parts per thousand if salinity is in PSU. Sea surface salinity is often abbreviated as "SSS". For the salinity of sea water at a particular depth or layer, a data variable of sea_water_salinity with a vertical coordinate axis should be used. sea_surface_salinity sea_surface_salinity "Amount" means mass per unit area. rainfall_amount rainfall_amount "Biomass burning carbon" refers to the rate at which biomass is burned by forest fires etc., expressed as the mass of carbon which it contains. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. biomass_burning_carbon_flux biomass_burning_carbon_flux air_pressure_at_freezing_level air_pressure_at_freezing_level The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. "Downward" indicates a vector component which is positive when directed downward (negative upward). The surface water flux is the result of precipitation and evaporation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downward_water_flux surface_downward_water_flux The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_radiance_in_air_reflected_by_sea_water surface_upwelling_radiance_in_air_reflected_by_sea_water Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tropopause_air_temperature tropopause_air_temperature A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. net_downward_longwave_flux_in_air_assuming_clear_sky net_downward_longwave_flux_in_air_assuming_clear_sky "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. 51 E133 hus specific_humidity specific_humidity The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). The vertical heat flux in air is the sum of all heat fluxes i.e. radiative, latent and sensible. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upward_heat_flux_in_air surface_upward_heat_flux_in_air "product_of_X_and_Y" means X*Y. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. product_of_eastward_wind_and_omega product_of_eastward_wind_and_omega The surface called "surface" means the lower boundary of the atmosphere. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. orog surface_altitude surface_altitude A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). Sea ice velocity is defined as a two-dimensional vector, with no vertical component. 96 northward_sea_ice_velocity northward_sea_ice_velocity 92 sit sea_ice_thickness sea_ice_thickness The surface called "surface" means the lower boundary of the atmosphere. surface_roughness_length_for_heat_in_air surface_roughness_length_for_heat_in_air Sound intensity is the sound energy per unit time per unit area. sound_intensity_in_air sound_intensity_in_air "longwave" means longwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. net_downward_longwave_flux_in_air net_downward_longwave_flux_in_air "shortwave" means shortwave radiation. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 116 net_upward_shortwave_flux_in_air net_upward_shortwave_flux_in_air "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. cloud_liquid_water_content_of_atmosphere_layer cloud_liquid_water_content_of_atmosphere_layer "Amount" means mass per unit area. The construction thickness_of_[X_]snowfall_amount means the accumulated "depth" of snow which fell i.e. the thickness of the layer of snow at its own density. There are corresponding standard names for liquid water equivalent (lwe) thickness. thickness_of_snowfall_amount thickness_of_snowfall_amount The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. surface_albedo_assuming_deep_snow surface_albedo_assuming_deep_snow The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_net_upward_radiative_flux surface_net_upward_radiative_flux The ocean mixed layer is the upper part of the ocean, regarded as being well-mixed. The base of the mixed layer defined by temperature, sigma or sigma_theta is the level at which the quantity indicated differs from its surface value by a certain amount. ocean_mixed_layer_thickness_defined_by_temperature ocean_mixed_layer_thickness_defined_by_temperature "product_of_X_and_Y" means X*Y. "specific" means per unit mass. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Specific humidity is the mass fraction of water vapor in (moist) air. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) product_of_eastward_wind_and_specific_humidity product_of_eastward_wind_and_specific_humidity "product_of_X_and_Y" means X*Y. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). Upward air velocity is the vertical component of the 3D air velocity vector. product_of_upward_air_velocity_and_air_temperature product_of_upward_air_velocity_and_air_temperature Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_rain_in_air mass_fraction_of_rain_in_air "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. volume_fraction_of_silt_in_soil volume_fraction_of_silt_in_soil In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. large_scale_rainfall_flux large_scale_rainfall_flux Downwelling radiation is radiation from above. It does not mean "net downward". Photon radiance is the photon flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. A photon flux is specified in terms of numbers of photons expressed in moles. downwelling_spectral_photon_radiance_in_sea_water downwelling_spectral_photon_radiance_in_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_water_vapor_flux_in_air_due_to_diffusion downward_water_vapor_flux_in_air_due_to_diffusion "lwe" means liquid water equivalent. "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) lwe_water_evaporation_rate lwe_water_evaporation_rate "longwave" means longwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. downwelling_longwave_radiance_in_air downwelling_longwave_radiance_in_air "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "Northward" indicates a vector component which is positive when directed northward (negative southward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. northward_water_vapor_transport_across_unit_distance_in_atmosphere_layer northward_water_vapor_transport_across_unit_distance_in_atmosphere_layer "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_water_vapor_flux_in_air upward_water_vapor_flux_in_air Sound pressure is the difference from the local ambient pressure caused by a sound wave at a particular location and time. Sound pressure level in air is expressed on a logarithmic scale with reference to a sound pressure of 2e-5 Pa. Lp = 20 log10(p/p0) where Lp is the sound pressure level, p is the rms sound pressure and p0 is the reference sound pressure. sound_pressure_level_in_air sound_pressure_level_in_air "Eastward" indicates a vector component which is positive when directed eastward (negative westward). "Upward" indicates a vector component which is positive when directed upward (negative downward). "Upward eastward" indicates the ZX component of a tensor. An upward eastward stress is an upward flux of eastward momentum, which accelerates the upper medium eastward and the lower medium westward. upward_eastward_stress_at_sea_ice_base upward_eastward_stress_at_sea_ice_base The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_spectral_radiance_in_sea_water surface_upwelling_spectral_radiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. "tendency_of_X" means derivative of X with respect to time. "Amount" means mass per unit area. Surface amount refers to the amount on the ground, excluding that on the plant or vegetation canopy. tendency_of_surface_snow_amount tendency_of_surface_snow_amount "product_of_X_and_Y" means X*Y. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. "omegaX" is used for brevity to mean "lagrangian_tendency_of_air_pressure in standard names constructed as a combination of omega with some other quantity. mpwapta product_of_omega_and_air_temperature product_of_omega_and_air_temperature The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_spectral_radiance_in_air_reflected_by_sea_water surface_upwelling_spectral_radiance_in_air_reflected_by_sea_water A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). 50 northward_sea_water_velocity northward_sea_water_velocity The surface called "surface" means the lower boundary of the atmosphere. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_carbon_dioxide_mole_flux surface_carbon_dioxide_mole_flux "longwave" means longwave radiation. "toa" means top of atmosphere. Adjusted forcing is the radiative flux change caused by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.) after allowance for stratospheric temperature adjustment. toa_adjusted_longwave_forcing toa_adjusted_longwave_forcing "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. eastward_water_vapor_transport_across_unit_distance_in_atmosphere_layer eastward_water_vapor_transport_across_unit_distance_in_atmosphere_layer The WMO definition of sunshine is that the surface incident radiative flux from the solar beam (i.e. excluding diffuse skylight) exceeds 120 W m-2. "Duration" is the length of time for which a condition holds. duration_of_sunshine duration_of_sunshine The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. surface_downwelling_photosynthetic_radiance_in_sea_water surface_downwelling_photosynthetic_radiance_in_sea_water "[horizontal_]divergence_of_X" means [horizontal] divergence of a vector X; if X does not have a vertical component then "horizontal" should be omitted. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) 44 E155 divergence_of_wind divergence_of_wind The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). surface_northward_sea_water_velocity surface_northward_sea_water_velocity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tnmmvgwd tendency_of_northward_wind_due_to_gravity_wave_drag tendency_of_northward_wind_due_to_gravity_wave_drag kg m-3 s-1 equivalent_temperature equivalent_temperature A velocity is a vector quantity. "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. The vertical mean land ice velocity is the average from the bedrock to the surface of the ice. land_ice_vertical_mean_x_velocity land_ice_vertical_mean_x_velocity Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upwelling_spectral_radiative_flux_in_sea_water upwelling_spectral_radiative_flux_in_sea_water A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). Upward air velocity is the vertical component of the 3D air velocity vector. 40 upward_air_velocity upward_air_velocity "shortwave" means shortwave radiation. Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.). tropopause_instantaneous_shortwave_forcing tropopause_instantaneous_shortwave_forcing Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. platform_pitch_angle platform_pitch_angle "X_area" means the horizontal area occupied by X within the grid cell. sea_area sea_area Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_evaporation_flux_where_sea_ice water_evaporation_flux_where_sea_ice "Amount" means mass per unit area. 78 convective_snowfall_amount convective_snowfall_amount In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rainfall_flux rainfall_flux Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) In meteorological reports, the direction of the wind vector is usually (but not always) given as the direction from which it is blowing (wind_from_direction) (westerly, northerly, etc.). In other contexts, such as atmospheric modelling, it is often natural to give the direction in the usual manner of vectors as the heading or the direction to which it is blowing (wind_to_direction) (eastward, southward, etc.) "from_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. 31 wind_from_direction wind_from_direction "Amount" means mass per unit area. "Water" means water in all phases, including frozen i.e. ice and snow. "Canopy" means the plant or vegetation canopy. The canopy water is the water on the canopy. canopy_water_amount canopy_water_amount ground_level means the land surface (beneath the snow and surface water, if any). "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_heat_flux_at_ground_level_in_soil downward_heat_flux_at_ground_level_in_soil The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "longwave" means longwave radiation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tntlw tendency_of_air_temperature_due_to_longwave_heating tendency_of_air_temperature_due_to_longwave_heating "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. volume_fraction_of_clay_in_soil volume_fraction_of_clay_in_soil Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. "Bedrock" is the solid Earth surface beneath land ice or ocean water. bedrock_altitude bedrock_altitude The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward). Upward air velocity is the vertical component of the 3D air velocity vector. tendency_of_upward_air_velocity_due_to_advection tendency_of_upward_air_velocity_due_to_advection "Content" indicates a quantity per unit area. liquid_water_content_of_snow_layer liquid_water_content_of_snow_layer "Downward" indicates a vector component which is positive when directed downward (negative upward). The vertical heat flux in air is the sum of all heat fluxes i.e. radiative, latent and sensible. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_heat_flux_in_air downward_heat_flux_in_air Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Spherical irradiance is the radiation incident on unit area of a hemispherical (or "2-pi") collector. It is sometimes called "scalar irradiance". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of "omnidirectional spherical irradiance". downwelling_spectral_spherical_irradiance_in_sea_water downwelling_spectral_spherical_irradiance_in_sea_water Forecast period is the time interval between the forecast reference time and the validity time. A period is an interval of time, or the time-period of an oscillation. forecast_period forecast_period "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Atmosphere potential vorticity is the vertically averaged absolute vorticity of a layer of the atmosphere divided by the pressure difference from the bottom to the top of the layer. potential_vorticity_of_atmosphere_layer potential_vorticity_of_atmosphere_layer "product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). The unit of salinity is PSU, which is dimensionless. The units attribute should be given as 1e-3 or 0.001 i.e. parts per thousand if salinity is in PSU. product_of_northward_sea_water_velocity_and_salinity product_of_northward_sea_water_velocity_and_salinity "toa" means top of atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. toa_net_downward_radiative_flux toa_net_downward_radiative_flux Potential density is the density a parcel of air or sea water would have if moved adiabatically to a reference pressure, by default assumed to be sea level pressure. For sea water potential density, if 1000 kg m-3 is subtracted, the standard name sea_water_sigma_theta should be chosen instead. sea_water_potential_density sea_water_potential_density The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_water_vapor_flux_in_air_due_to_diffusion upward_water_vapor_flux_in_air_due_to_diffusion "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Dry energy is the sum of dry static energy and kinetic energy. Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. atmosphere_dry_energy_content atmosphere_dry_energy_content The surface called "surface" means the lower boundary of the atmosphere. Upwelling radiation is radiation from below. It does not mean "net upward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_upwelling_spectral_radiative_flux_in_air surface_upwelling_spectral_radiative_flux_in_air "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. 81 sftlf land_area_fraction land_area_fraction "longwave" means longwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. tropopause_downwelling_longwave_flux tropopause_downwelling_longwave_flux sea_level means mean sea level, which is close to the geoid in sea areas. "Sea surface height" is a time-varying quantity. The standard name for the height of the sea surface above the geoid is sea_surface_height_above_geoid. 82 sea_surface_height_above_sea_level sea_surface_height_above_sea_level "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Quantities defined for a soil layer must have a vertical coordinate variable with boundaries indicating the extent of the layer(s). liquid_water_content_of_soil_layer liquid_water_content_of_soil_layer "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. atmosphere_kinetic_energy_content atmosphere_kinetic_energy_content Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_sulfur_dioxide_in_air mass_fraction_of_sulfur_dioxide_in_air The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_photosynthetic_radiative_flux_in_sea_water surface_downwelling_photosynthetic_radiative_flux_in_sea_water "product_of_X_and_Y" means X*Y. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. It is numerically similar to the altitude (or geometric height) and not to the quantity with standard name height, which is relative to the surface. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpuzga product_of_eastward_wind_and_geopotential_height product_of_eastward_wind_and_geopotential_height ground_level means the land surface (beneath the snow and surface water, if any). "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_heat_flux_at_ground_level_in_soil upward_heat_flux_at_ground_level_in_soil Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. Spherical irradiance is the radiation incident on unit area of a hemispherical (or "2-pi") collector. It is sometimes called "scalar irradiance". The direction (up/downwelling) is specified. Radiation incident on a 4-pi collector has standard names of "omnidirectional spherical irradiance". downwelling_photosynthetic_spherical_irradiance_in_sea_water downwelling_photosynthetic_spherical_irradiance_in_sea_water Downwelling radiation is radiation from above. It does not mean "net downward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. downwelling_radiance_in_sea_water downwelling_radiance_in_sea_water Height is the vertical distance above the surface. "Canopy" means the plant or vegetation canopy. canopy_height canopy_height The surface called "surface" means the lower boundary of the atmosphere. Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. surface_snow_thickness_where_sea_ice surface_snow_thickness_where_sea_ice Height is the vertical distance above the surface. 100 sea_surface_wave_significant_height sea_surface_wave_significant_height "product_of_X_and_Y" means X*Y. "specific" means per unit mass. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) product_of_northward_wind_and_specific_humdity product_of_northward_wind_and_specific_humdity See Appendix D of the CF convention for information about dimensionless vertical coordinates. atmosphere_sleve_coordinate atmosphere_sleve_coordinate Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). clw mass_fraction_of_cloud_liquid_water_in_air mass_fraction_of_cloud_liquid_water_in_air "wrt" means with respect to. Speed is the magnitude of velocity. Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. The platform speed with respect to ground is relative to the solid Earth beneath it i.e. the sea floor for a ship. It is often called the "ground speed" of the platform. platform_speed_wrt_ground platform_speed_wrt_ground "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. eastward_atmosphere_water_vapor_transport_across_unit_distance eastward_atmosphere_water_vapor_transport_across_unit_distance "condensed_water" means liquid and ice. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_cloud_condensed_water_in_air mass_fraction_of_cloud_condensed_water_in_air Soil suction is the tensile stress on water in soil due to molecular forces acting at the water-soil particle boundary. The forces may cause water to be drawn into the spaces within the soil matrix or cause it to be held in the soil without draining. Soil suction occurs in soil above the water table. soil_suction_at_saturation soil_suction_at_saturation "tendency_of_X" means derivative of X with respect to time. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). tendency_of_mass_fraction_of_cloud_ice_in_air tendency_of_mass_fraction_of_cloud_ice_in_air The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by bolus advection in an ocean model means the part due to a scheme representing eddy-induced effects not included in the velocity field. northward_ocean_salt_transport_due_to_bolus_advection northward_ocean_salt_transport_due_to_bolus_advection "Amount" means mass per unit area. sea_ice_amount sea_ice_amount Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_photosynthetic_photon_flux_in_sea_water downwelling_photosynthetic_photon_flux_in_sea_water "product_of_X_and_Y" means X*Y. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) product_of_eastward_wind_and_air_temperature product_of_eastward_wind_and_air_temperature "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. Projection coordinates are distances in the x- and y-directions on a plane onto which the surface of the Earth has been projected according to a map projection. The relationship between the projection coordinates and latitude and longitude is described by the grid_mapping. projection_y_coordinate projection_y_coordinate A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. "toa" means top of atmosphere. The TOA outgoing longwave flux is the upwelling thermal radiative flux, often called the "outgoing longwave radiation" or "OLR". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rlutcs toa_outgoing_longwave_flux_assuming_clear_sky toa_outgoing_longwave_flux_assuming_clear_sky Sound intensity is the sound energy per unit time per unit area. Sound intensity level in water is expressed on a logarithmic scale with reference to a sound intensity of 6.7e-19 W m-2. LI = 10 log10(I/I0) where LI is sound intensity level, I is sound intensity and I0 is the reference sound intensity. sound_intensity_level_in_water sound_intensity_level_in_water m2 s-1 rad-1 The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "shortwave" means shortwave radiation. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tntsw tendency_of_air_temperature_due_to_shortwave_heating tendency_of_air_temperature_due_to_shortwave_heating Soil temperature is the bulk temperature of the soil, not the surface (skin) temperature. 85 soil_temperature soil_temperature Downwelling radiation is radiation from above. It does not mean "net downward". Photon spherical irradiance is the photon flux incident on unit area of a hemispherical (or "2-pi") collector. A photon flux is specified in terms of numbers of photons expressed in moles. downwelling_photon_spherical_irradiance_in_sea_water downwelling_photon_spherical_irradiance_in_sea_water "tendency_of_X" means derivative of X with respect to time. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. tendency_of_land_ice_thickness tendency_of_land_ice_thickness The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsuscs surface_upwelling_shortwave_flux_in_air_assuming_clear_sky surface_upwelling_shortwave_flux_in_air_assuming_clear_sky The surface called "surface" means the lower boundary of the atmosphere. Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_diffuse_downwelling_photosynthetic_radiative_flux_in_air surface_diffuse_downwelling_photosynthetic_radiative_flux_in_air Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. tropopause_altitude tropopause_altitude "Amount" means mass per unit area. "Water" means water in all phases. Evaporation is the conversion of liquid or solid into vapor. (The conversion of solid alone into vapor is called "sublimation".) 57 water_evaporation_amount water_evaporation_amount pseudo_equivalent_temperature pseudo_equivalent_temperature A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "shortwave" means shortwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsntpcs net_downward_shortwave_flux_in_air_assuming_clear_sky net_downward_shortwave_flux_in_air_assuming_clear_sky "integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature excess is the air temperature minus the air temperature threshold. Its integral with respect to time is often called after its units of "degree-days". integral_of_air_temperature_excess_wrt_time integral_of_air_temperature_excess_wrt_time The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tendency_of_air_temperature_due_to_radiative_heating tendency_of_air_temperature_due_to_radiative_heating The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. tendency_of_specific_humidity_due_to_advection tendency_of_specific_humidity_due_to_advection Speed is the magnitude of velocity. speed_of_sound_in_sea_water speed_of_sound_in_sea_water 1 plev air_pressure air_pressure "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) geostrophic_northward_wind geostrophic_northward_wind The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The volume scattering/absorption/attenuation coefficient is the fractional change of radiative flux per unit path length due to the stated process. Coefficients with canonical units of m2 s-1 i.e. multiplied by density have standard names with specific_ instead of volume_. The scattering/absorption/attenuation coefficient is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength is included to specify the wavelength. volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter "longwave" means longwave radiation. "Downward" indicates a vector component which is positive when directed downward (negative upward). Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. tropopause_net_downward_longwave_flux tropopause_net_downward_longwave_flux rainfall_rate rainfall_rate The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. tendency_of_atmosphere_water_vapor_content_due_to_turbulence tendency_of_atmosphere_water_vapor_content_due_to_turbulence Sound pressure is the difference from the local ambient pressure caused by a sound wave at a particular location and time. sound_pressure_in_air sound_pressure_in_air The surface called "surface" means the lower boundary of the atmosphere. A phrase assuming_condition indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition. "longwave" means longwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rldscs surface_downwelling_longwave_flux_in_air_assuming_clear_sky surface_downwelling_longwave_flux_in_air_assuming_clear_sky Frequency is the number of oscillations of a wave per unit time. brunt_vaisala_frequency_in_air brunt_vaisala_frequency_in_air "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) 33 E131 ua eastward_wind eastward_wind Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). Convective cloud is that produced by the convection schemes in an atmosphere model. mass_fraction_of_convective_cloud_liquid_water_in_air mass_fraction_of_convective_cloud_liquid_water_in_air A variable with the standard name of soil_type contains strings which indicate the character of the soil e.g. clay. These strings have not yet been standardised. Alternatively, the data variable may contain integers which can be translated to strings using flag_values and flag_meanings attributes. soil_type soil_type Gross primary productivity is the rate of synthesis of biomass per unit area from inorganic precursors by autotrophs, especially by photosynthesising plants using sunlight for energy. The producers also respire some of this biomass and the difference is net_primary_producivity. "Productivity of carbon" refers to the production of biomass expressed as the mass of carbon which it contains. gross_primary_productivity_of_carbon gross_primary_productivity_of_carbon Potential temperature is the temperature a parcel of air or sea water would have if moved adiabatically to sea level pressure. 13 theta air_potential_temperature air_potential_temperature "shortwave" means shortwave radiation. Downwelling radiation is radiation from above. It does not mean "net downward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_shortwave_flux_in_air downwelling_shortwave_flux_in_air snow_grain_size snow_grain_size "shortwave" means shortwave radiation. "toa" means top of atmosphere. The TOA incoming shortwave flux is the radiative flux from the sun i.e. the "downwelling" TOA shortwave flux. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsdt toa_incoming_shortwave_flux toa_incoming_shortwave_flux "Upward" indicates a vector component which is positive when directed upward (negative downward). The vertical heat flux in air is the sum of all heat fluxes i.e. radiative, latent and sensible. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_heat_flux_in_air upward_heat_flux_in_air Downwelling radiation is radiation from above. It does not mean "net downward". Photon radiance is the photon flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. A photon flux is specified in terms of numbers of photons expressed in moles. downwelling_photosynthetic_photon_radiance_in_sea_water downwelling_photosynthetic_photon_radiance_in_sea_water "toa" means top of atmosphere. Adjusted forcing is the radiative flux change caused by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.) after allowance for stratospheric temperature adjustment. toa_adjusted_radiative_forcing toa_adjusted_radiative_forcing "Amount" means mass per unit area. 61 precipitation_amount precipitation_amount A velocity is a vector quantity. "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. sea_ice_x_velocity sea_ice_x_velocity moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y. moles_of_oxygen_per_unit_mass_in_sea_water moles_of_oxygen_per_unit_mass_in_sea_water "longwave" means longwave radiation. Radiance is the radiative flux in a particular direction, per unit of solid angle. If radiation is isotropic, the radiance is independent of direction, so the direction should not be specified. If the radiation is directionally dependent, a standard name of upwelling or downwelling radiance should be chosen instead. isotropic_longwave_radiance_in_air isotropic_longwave_radiance_in_air "shortwave" means shortwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upwelling_shortwave_flux_in_air upwelling_shortwave_flux_in_air cloud_top refers to the top of the highest cloud. Convective cloud is that produced by the convection schemes in an atmosphere model. air_pressure_at_convective_cloud_top air_pressure_at_convective_cloud_top Sea surface temperature is usually abbreviated as "SST". It is the temperature of sea water near the surface (including the part under sea-ice, if any), and not the skin temperature, whose standard name is surface_temperature. For the temperature of sea water at a particular depth or layer, a data variable of sea_water_temperature with a vertical coordinate axis should be used. sea_surface_temperature sea_surface_temperature Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). cli mass_fraction_of_cloud_ice_in_air mass_fraction_of_cloud_ice_in_air "product_of_X_and_Y" means X*Y. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity. It is numerically similar to the altitude (or geometric height) and not to the quantity with standard name height, which is relative to the surface. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpvzga product_of_northward_wind_and_geopotential_height product_of_northward_wind_and_geopotential_height The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tendency_of_air_temperature_due_to_turbulence tendency_of_air_temperature_due_to_turbulence atmosphere_heat_diffusivity atmosphere_heat_diffusivity Water vapor saturation deficit is the difference between the saturation water vapor pressure and the actual water vapor pressure. 56 water_vapor_saturation_deficit water_vapor_saturation_deficit The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Upwelling radiation is radiation from below. It does not mean "net upward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_upwelling_radiance_in_air_emerging_from_sea_water surface_upwelling_radiance_in_air_emerging_from_sea_water "shortwave" means shortwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. upwelling_shortwave_radiance_in_air upwelling_shortwave_radiance_in_air "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) 34 E132 va northward_wind northward_wind "Water" means water in all phases. Sublimation is the conversion of solid into vapor. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. water_sublimation_flux water_sublimation_flux "longwave" means longwave radiation. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 115 net_upward_longwave_flux_in_air net_upward_longwave_flux_in_air "longwave" means longwave radiation. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Net absorbed radiation is the difference between absorbed and emitted radiation. net_rate_of_absorption_of_longwave_energy_in_atmosphere_layer net_rate_of_absorption_of_longwave_energy_in_atmosphere_layer The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_photosynthetic_photon_flux_in_sea_water surface_downwelling_photosynthetic_photon_flux_in_sea_water Solar azimuth angle is the horizontal angle between the line of sight to the sun and a reference direction which is often due north. The angle is measured clockwise. solar_azimuth_angle solar_azimuth_angle "product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). product_of_northward_sea_water_velocity_and_temperature product_of_northward_sea_water_velocity_and_temperature "frozen_water" means ice. "Content" indicates a quantity per unit area. The "soil content" of a quantity refers to the vertical integral from the surface down to the bottom of the soil model. For the content between specified levels in the soil, standard names including content_of_soil_layer are used. mrfso soil_frozen_water_content soil_frozen_water_content "Respiration carbon" refers to the rate at which biomass is respired expressed as the mass of carbon which it contains. Soil respiration is the sum of respiration in the soil by animals and decomposers of litter (heterotrophs or "consumers"), which have not produced the biomass they respire, and respiration by the roots of plants (autotrophs or "producers"), which have themselves produced the biomass they respire. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. soil_respiration_carbon_flux soil_respiration_carbon_flux Speed is the magnitude of velocity. 94 sea_ice_speed sea_ice_speed "tendency_of_X" means derivative of X with respect to time. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). tendency_of_mass_fraction_of_cloud_liquid_water_in_air tendency_of_mass_fraction_of_cloud_liquid_water_in_air The surface called "surface" means the lower boundary of the atmosphere. Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_spectral_radiative_flux_in_air surface_downwelling_spectral_radiative_flux_in_air The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. tendency_of_water_vapor_content_of_atmosphere_layer_due_to_turbulence tendency_of_water_vapor_content_of_atmosphere_layer_due_to_turbulence "lwe" means liquid water equivalent. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock. Specific mass balance means the net rate at which ice is added per unit area at the land ice surface. land_ice_lwe_surface_specific_mass_balance land_ice_lwe_surface_specific_mass_balance The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. "Water" means water in all phases. tendency_of_atmosphere_water_content_due_to_advection tendency_of_atmosphere_water_content_due_to_advection "Water" means water in all phases. "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. volume_fraction_of_water_in_soil volume_fraction_of_water_in_soil "X_area" means the horizontal area occupied by X within the grid cell. sea_ice_area sea_ice_area Potential temperature is the temperature a parcel of air or sea water would have if moved adiabatically to sea level pressure. 14 pseudo_equivalent_potential_temperature pseudo_equivalent_potential_temperature The surface called "surface" means the lower boundary of the atmosphere. surface_drag_coefficient_for_momentum_in_air surface_drag_coefficient_for_momentum_in_air The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tendency_of_eastward_wind_due_to_advection tendency_of_eastward_wind_due_to_advection Sea surface wave directional variance spectral density is the variance of the amplitude of the waves within given ranges of direction and wave frequency. sea_surface_wave_directional_variance_spectral_density sea_surface_wave_directional_variance_spectral_density Sound intensity is the sound energy per unit time per unit area. Sound intensity level in air is expressed on a logarithmic scale with reference to a sound intensity of 1e-12 W m-2. LI = 10 log10(I/I0) where LI is sound intensity level, I is sound intensity and I0 is the reference sound intensity. sound_intensity_level_in_air sound_intensity_level_in_air "X_area" means the horizontal area occupied by X within the grid cell. leaf_area_index leaf_area_index "specific" means per unit mass. specific_kinetic_energy_of_air specific_kinetic_energy_of_air The surface called "surface" means the lower boundary of the atmosphere. "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. snc surface_snow_area_fraction surface_snow_area_fraction The surface called "surface" means the lower boundary of the atmosphere. Downwelling radiation is radiation from above. It does not mean "net downward". "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_photosynthetic_photon_flux_in_air surface_downwelling_photosynthetic_photon_flux_in_air "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_heat_flux_in_soil downward_heat_flux_in_soil "Water" means water in all phases. The water flux or volume transport into the ocean from rivers is the inflow to the ocean, often applied to the surface in ocean models. water_volume_transport_into_ocean_from_rivers water_volume_transport_into_ocean_from_rivers The surface called "surface" means the lower boundary of the atmosphere. "tendency_of_X" means derivative of X with respect to time. E158 tendency_of_surface_air_pressure tendency_of_surface_air_pressure The geoid is a surface of constant geopotential with which mean sea level would coincide if the ocean were at rest. (The volume enclosed between the geoid and the sea floor equals the mean volume of water in the ocean.) In an ocean GCM the geoid is the surface of zero depth, or the rigid lid if the model uses that approximation. zobt sea_floor_depth_below_geoid sea_floor_depth_below_geoid "Amount" means mass per unit area. 63 convective_precipitation_amount convective_precipitation_amount The surface called "surface" means the lower boundary of the atmosphere. Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. surface_temperature_where_open_sea surface_temperature_where_open_sea "longwave" means longwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction towards which it is going must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. upwelling_longwave_radiance_in_air upwelling_longwave_radiance_in_air Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. platform_roll_angle platform_roll_angle "tendency_of_X" means derivative of X with respect to time. tendency_of_air_density tendency_of_air_density "shortwave" means shortwave radiation. Adjusted forcing is the radiative flux change caused by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.) after allowance for stratospheric temperature adjustment. tropopause_adjusted_shortwave_forcing tropopause_adjusted_shortwave_forcing A period is an interval of time, or the time-period of an oscillation. The zero upcrossing period is defined as the time interval between consecutive occasions on which the surface height passes upward above the mean level. sea_surface_wave_zero_upcrossing_period sea_surface_wave_zero_upcrossing_period The surface called "surface" means the lower boundary of the atmosphere. "shortwave" means shortwave radiation. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 111 E177 surface_net_upward_shortwave_flux surface_net_upward_shortwave_flux See Appendix D of the CF convention for information about dimensionless vertical coordinates. ocean_s_coordinate ocean_s_coordinate "tendency_of_X" means derivative of X with respect to time. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tnmmvtot tendency_of_northward_wind tendency_of_northward_wind The surface called "surface" means the lower boundary of the atmosphere. "shortwave" means shortwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rsus surface_upwelling_shortwave_flux_in_air surface_upwelling_shortwave_flux_in_air Sound intensity is the sound energy per unit time per unit area. sound_intensity_in_water sound_intensity_in_water "integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Depth is the vertical distance below the surface. ocean_integral_of_sea_water_temperature_wrt_depth ocean_integral_of_sea_water_temperature_wrt_depth The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by (meridional) overturning is geometrically defined as being the part due to the vertical integral of the product of zonal means of velocity and tracer. The velocity does not include "bolus" or Gent-McWilliams velocity. htovovrt northward_ocean_heat_transport_due_to_overturning northward_ocean_heat_transport_due_to_overturning "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. "Downward" indicates a vector component which is positive when directed downward (negative upward). downward_x_stress_at_sea_ice_base downward_x_stress_at_sea_ice_base "lwe" means liquid water equivalent. The construction lwe_thickness_of_X_amount or _content means the vertical extent of a layer of liquid water having the same mass per unit area. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. E137 lwe_thickness_of_atmosphere_water_vapor_content lwe_thickness_of_atmosphere_water_vapor_content "Content" indicates a quantity per unit area. snow_soot_content snow_soot_content Speed is the magnitude of velocity. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) The wind speed is the magnitude of the wind velocity. Wind speed shear is the derivative of wind speed with respect to height. N136 wind_speed_shear wind_speed_shear "tendency_of_X" means derivative of X with respect to time. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. tendency_of_air_temperature tendency_of_air_temperature The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). The surface latent heat flux is the exchange of heat between the surface and the air on account of evaporation (including sublimation). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 121 E147 hfls surface_upward_latent_heat_flux surface_upward_latent_heat_flux Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. altitude_at_top_of_dry_convection altitude_at_top_of_dry_convection Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_spectral_radiative_flux_in_air downwelling_spectral_radiative_flux_in_air Downwelling radiation is radiation from above. It does not mean "net downward". A photon flux is specified in terms of numbers of photons expressed in moles. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_photon_flux_in_sea_water downwelling_photon_flux_in_sea_water "longwave" means longwave radiation. "toa" means top of atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. toa_net_upward_longwave_flux toa_net_upward_longwave_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "condensed_water" means liquid and ice. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). tendency_of_mass_fraction_of_cloud_condensed_water_in_air_due_to_advection tendency_of_mass_fraction_of_cloud_condensed_water_in_air_due_to_advection "shortwave" means shortwave radiation. "toa" means top of atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). Net upward radiation is the difference between radiation from below (upwelling) and radiation from above (downwelling). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 113 E178 toa_net_upward_shortwave_flux toa_net_upward_shortwave_flux A period is an interval of time, or the time-period of an oscillation. Swell waves are waves on the ocean surface. 106 sea_surface_swell_wave_period sea_surface_swell_wave_period "square_of_X" means X*X. Frequency is the number of oscillations of a wave per unit time. N138 square_of_brunt_vaisala_frequency_in_air square_of_brunt_vaisala_frequency_in_air In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. convective_snowfall_flux convective_snowfall_flux The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Atmosphere water vapor content is sometimes referred to as "precipitable water", although this term does not imply the water could all be precipitated. tendency_of_atmosphere_water_vapor_content_due_to_advection tendency_of_atmosphere_water_vapor_content_due_to_advection "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. "Downward" indicates a vector component which is positive when directed downward (negative upward). downward_y_stress_at_sea_ice_base downward_y_stress_at_sea_ice_base The surface called "surface" means the lower boundary of the atmosphere. surface_drag_coefficient_in_air surface_drag_coefficient_in_air "shortwave" means shortwave radiation. "toa" means top of atmosphere. Adjusted forcing is the radiative flux change caused by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.) after allowance for stratospheric temperature adjustment. toa_adjusted_shortwave_forcing toa_adjusted_shortwave_forcing The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by bolus advection in an ocean model means the part due to a scheme representing eddy-induced effects not included in the velocity field. northward_ocean_heat_transport_due_to_bolus_advection northward_ocean_heat_transport_due_to_bolus_advection "Water" means water in all phases. "Northward" indicates a vector component which is positive when directed northward (negative southward). Transport across_unit_distance means expressed per unit distance normal to the direction of transport. northward_atmosphere_water_transport_across_unit_distance northward_atmosphere_water_transport_across_unit_distance Longitude is positive eastward; its units of degree_east (or equivalent) indicate this explicitly. In a latitude-longitude system defined with respect to a rotated North Pole, the standard name of grid_longitude should be used instead of longitude. Grid longitude is positive in the grid-eastward direction, but its units should be plain degree. grid_longitude grid_longitude "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_heat_flux_in_sea_ice downward_heat_flux_in_sea_ice sea_ice_mass sea_ice_mass "Content" indicates a quantity per unit area. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). trsult atmosphere_content_of_sulfate_aerosol atmosphere_content_of_sulfate_aerosol The soil porosity is the proportion of its total volume not occupied by soil solids. soil_porosity soil_porosity Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). Convective cloud is that produced by the convection schemes in an atmosphere model. mass_fraction_of_convective_cloud_ice_in_air mass_fraction_of_convective_cloud_ice_in_air "product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). "Upward" indicates a vector component which is positive when directed upward (negative downward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) Upward air velocity is the vertical component of the 3D air velocity vector. product_of_eastward_wind_and_upward_air_velocity product_of_eastward_wind_and_upward_air_velocity The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Downward" indicates a vector component which is positive when directed downward (negative upward). Dry static energy is the sum of enthalpy and potential energy (itself the sum of gravitational and centripetal potential energy). Enthalpy can be written either as (1) CpT, where Cp is heat capacity at constant pressure, T is absolute temperature, or (2) U+pV, where U is internal energy, p is pressure and V is volume. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downward_dry_static_energy_flux_due_to_diffusion downward_dry_static_energy_flux_due_to_diffusion "Amount" means mass per unit area. The construction thickness_of_[X_]rainfall_amount means the accumulated "depth" of rainfall i.e. the thickness of a layer of liquid water having the same mass per unit area as the rainfall amount. thickness_of_convective_rainfall_amount thickness_of_convective_rainfall_amount Air temperature is the bulk temperature of the air, not the surface (skin) temperature. A lapse rate is the negative derivative of a quantity with respect to increasing height above the surface, or the (positive) derivative with respect to increasing depth. 19 air_temperature_lapse_rate air_temperature_lapse_rate The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Potential energy is the sum of the gravitational potential energy relative to the geoid and the centripetal potential energy. (The geopotential is the specific potential energy.) tendency_of_potential_energy_content_of_atmosphere_layer_due_to_advection tendency_of_potential_energy_content_of_atmosphere_layer_due_to_advection "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. sea_area_fraction sea_area_fraction "X_area_fraction" means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. Sea ice area fraction is area of the sea surface occupied by sea ice. It is also called "sea ice concentration". 91 sic sea_ice_area_fraction sea_ice_area_fraction Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_spectral_radiative_flux_in_sea_water downwelling_spectral_radiative_flux_in_sea_water The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. tendency_of_water_vapor_content_of_atmosphere_layer_due_to_convection tendency_of_water_vapor_content_of_atmosphere_layer_due_to_convection sea_ice_temperature sea_ice_temperature The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air. tnmrc tendency_of_specific_humidity_due_to_convection tendency_of_specific_humidity_due_to_convection cloud_top refers to the top of the highest cloud. Height is the vertical distance above the surface. height_at_cloud_top height_at_cloud_top Radiative flux is the sum of shortwave and longwave radiative fluxes. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The volume scattering/absorption/attenuation coefficient is the fractional change of radiative flux per unit path length due to the stated process. Coefficients with canonical units of m2 s-1 i.e. multiplied by density have standard names with specific_ instead of volume_. The scattering/absorption/attenuation coefficient is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength is included to specify the wavelength. Scattering of radiation is its deflection from its incident path without loss of energy. The (range of) direction(s) of scattering can be specified by a coordinate of scattering_angle. volume_scattering_coefficient_of_radiative_flux_in_sea_water volume_scattering_coefficient_of_radiative_flux_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. surface_drag_coefficient_for_heat_in_air surface_drag_coefficient_for_heat_in_air Soil albedo is the albedo of the soil surface assuming no snow. soil_albedo soil_albedo "Water" means water in all phases. "Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y. The wilting point of soil is the water content below which plants cannot extract sufficient water to balance their loss through transpiration. volume_fraction_of_water_in_soil_at_wilting_point volume_fraction_of_water_in_soil_at_wilting_point The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "tendency_of_X" means derivative of X with respect to time. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) tendency_of_eastward_wind_due_to_diffusion tendency_of_eastward_wind_due_to_diffusion Speed is the magnitude of velocity. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) The wind speed is the magnitude of the wind velocity. 32 wind_speed wind_speed ground_level means the land surface (beneath the snow and surface water, if any). "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. upward_heat_flux_at_ground_level_in_snow upward_heat_flux_at_ground_level_in_snow cloud_base refers to the base of the lowest cloud. Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level. cloud_base_altitude cloud_base_altitude Downwelling radiation is radiation from above. It does not mean "net downward". Radiative flux is the sum of shortwave and longwave radiative fluxes. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. downwelling_radiative_flux_in_sea_water downwelling_radiative_flux_in_sea_water convective_rainfall_rate convective_rainfall_rate "wrt" means with respect to. Speed is the magnitude of velocity. Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship. platform_speed_wrt_sea_water platform_speed_wrt_sea_water "Content" indicates a quantity per unit area. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. Potential energy is the sum of the gravitational potential energy relative to the geoid and the centripetal potential energy. (The geopotential is the specific potential energy.) potential_energy_content_of_atmosphere_layer potential_energy_content_of_atmosphere_layer The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. surface_downwelling_spectral_radiative_flux_in_sea_water surface_downwelling_spectral_radiative_flux_in_sea_water Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. Photon spherical irradiance is the photon flux incident on unit area of a hemispherical (or "2-pi") collector. A photon flux is specified in terms of numbers of photons expressed in moles. downwelling_spectral_photon_spherical_irradiance_in_sea_water downwelling_spectral_photon_spherical_irradiance_in_sea_water In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. large_scale_precipitation_flux large_scale_precipitation_flux The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). The surface sensible heat flux, also called "turbulent" heat flux, is the exchange of heat between the surface and the air by motion of air. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 122 E146 hfss surface_upward_sensible_heat_flux surface_upward_sensible_heat_flux "product_of_X_and_Y" means X*Y. A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). "Upward" indicates a vector component which is positive when directed upward (negative downward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) Upward air velocity is the vertical component of the 3D air velocity vector. product_of_northward_wind_and_upward_air_velocity product_of_northward_wind_and_upward_air_velocity The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Photon radiance is the photon flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. A photon flux is specified in terms of numbers of photons expressed in moles. surface_downwelling_spectral_photon_radiance_in_sea_water surface_downwelling_spectral_photon_radiance_in_sea_water The surface called "surface" means the lower boundary of the atmosphere. "longwave" means longwave radiation. Upwelling radiation is radiation from below. It does not mean "net upward". When thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. rlus surface_upwelling_longwave_flux_in_air surface_upwelling_longwave_flux_in_air Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where_type specifies instead that the quantity applies only to the part of the grid box of the named type. "Canopy" means the plant or vegetation canopy. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. prveg precipitation_flux_onto_canopy_where_land precipitation_flux_onto_canopy_where_land Downwelling radiation is radiation from above. It does not mean "net downward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. "Photosynthetic" radiation is the part of the spectrum which is used in photosynthesis e.g. 300-700 nm. The range of wavelengths could be specified precisely by the bounds of a coordinate of radiation_wavelength. downwelling_photosynthetic_radiance_in_sea_water downwelling_photosynthetic_radiance_in_sea_water "condensed_water" means liquid and ice. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of Y to the mass of X (including Y). mass_fraction_of_convective_condensed_water_in_air mass_fraction_of_convective_condensed_water_in_air A period is an interval of time, or the time-period of an oscillation. The zero upcrossing period is defined as the time interval between consecutive occasions on which the surface height passes upward above the mean level. Wind waves are waves on the ocean surface. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) sea_surface_wind_wave_zero_upcrossing_period sea_surface_wind_wave_zero_upcrossing_period "ratio_of_X_to_Y" means X/Y. "stp" means standard temperature (0 degC) and pressure (101325 Pa). volume_mixing_ratio_of_oxygen_at_stp_in_sea_water volume_mixing_ratio_of_oxygen_at_stp_in_sea_water Sea ice draft is the depth of the sea-ice lower surface below the water surface. sea_ice_draft sea_ice_draft The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. Downwelling radiation is radiation from above. It does not mean "net downward". Radiance is the radiative flux in a particular direction, per unit of solid angle. The direction from which it is coming must be specified, for instance with a coordinate of zenith_angle. If the radiation does not depend on direction, a standard name of isotropic radiance should be chosen instead. surface_downwelling_radiance_in_sea_water surface_downwelling_radiance_in_sea_water Adjusted forcing is the radiative flux change caused by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.) after allowance for stratospheric temperature adjustment. tropopause_adjusted_radiative_forcing tropopause_adjusted_radiative_forcing The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Northward" indicates a vector component which is positive when directed northward (negative southward). Northward transport by (meridional) overturning is geometrically defined as being the part due to the vertical integral of the product of zonal means of velocity and tracer. The velocity does not include "bolus" or Gent-McWilliams velocity. northward_ocean_freshwater_transport_due_to_overturning northward_ocean_freshwater_transport_due_to_overturning "square_of_X" means X*X. "Northward" indicates a vector component which is positive when directed northward (negative southward). Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name upward_air_velocity.) mpvva square_of_northward_wind square_of_northward_wind The surface called "surface" means the lower boundary of the atmosphere. "Water" means water in all phases, including frozen i.e. ice and snow. A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). surface_eastward_sea_water_velocity surface_eastward_sea_water_velocity