CF standard names

The standard names have been constructed using the rules described here. The rules are provided to help interpret the names and to suggest how new names should be derived.

Generic names

The table begins with some generic names. These may be used as standard names, but most of them are not sufficiently specific to be often appropriate. However, many of the later entries are based on the generic names. A standard name containing a phrase which is a generic name implies the same unit as that generic name.

Special phrases

Some words and phrases have particular meanings which should be made clear.

water => water in all phases
condensed_water => liquid and ice
frozen_water => ice
unfrozen_water => liquid and vapour
shortwave/longwave => shortwave/longwave radiation
area => horizontal area unless otherwise stated
anomaly => difference from climatology
sea_water and air are used for local quantities, as opposed to ...
ocean and atmosphere for large-scale properties
specific => per unit mass
molar => per mole
TOA => top of atmosphere
LWE => liquid water equivalent
wrt => with respect to

Qualifications

Standard names may be further clarified by the addition of phrases in certain standard forms and order. All of the following phrases in [] are optional. The words in typewriter type appear explicitly as stated, while the words in italic indicate other words or phrases to be substituted. As usual, the whole standard name is joined up with underscores.

[surface] [component] [medium] base_standard_name [at surface] [in medium] [due to process] [where type] [assuming condition]

A surface is one defined as a function of horizontal position. Some of them are single words which are placed at the start: TOA (top of atmosphere), tropopause, surface. The multi-word phrases adiabatic_condensation_level, cloud_top, convective_cloud_top, cloud_base, convective_cloud_base, freezing_level, maximum_wind_speed_level, sea_floor, sea_level, sea_ice_surface, sea_ice_base are put after at. The surface surface means the lower boundary of the atmosphere, and sea_level means mean sea level, which is close to the geoid in sea areas. Surfaces which are defined using a coordinate value (e.g. height of 1.5 m) are not represented by the standard name; they should be shown by a single-valued coordinate variable.

A component indicates the direction of the spatial component of a vector. It is one of the words upward, downward, northward, southward, eastward, westward. The presence of one of these words implies "component of". If the standard_name indicates a tensor quantity, two of these direction words may be included, applying to two of the spatial dimensions Z Y X, in that order. If only one component is indicated for a tensor, it means the flux in the indicated direction of the magnitude of the vector quantity in the plane of the other two spatial dimensions. If preceded by the word grid, the components indicate directions along the horizontal grid being used, which may not coincide with true longitude and latitude (if there is a rotated pole, for instance).

A medium indicates the material medium to which the quantity applies e.g. air.

The specification of a physical 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 process phrase. For instance, the upward heat flux in the ocean is a sum of terms due to advection, diffusion, convection and so on.

Unless indicated, a quantity is assumed to apply to the whole area of each horizontal grid box. The qualifier where specifies instead that the quantity applies only to the part of the grid box of the named type e.g. where_cloud, where_sea_ice, where_land, where_vegetation.

A condition phrase 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 e.g. the vertical radiative heat flux recalculated for clear sky, as if the clouds were not present.

Transformations

Standard names may be derived from other standard names (represented here by X and Y) by the following rules. When X and Y both appear, they should be ordered alphabetically. Transformations can be nested. Transformations may alter the units as shown.

ruleunitsclarification
direction_of_Xdegreedirection of a vector, a bearing
magnitude_of_X[X]magnitude of a vector X
square_of_X[X]*[X]X*X
rate_of_change_of_X[X] s-1derivative of X with respect to time
[grid_]component_derivative_of_X[X] m-1derivative of X with respect to distance in the component direction, which may be northward, southward, eastward or westward
divergence_of_X[X] m-1divergence of a vector X
product_of_X_and_Y[X]*[Y]X*Y
ratio_of_X_to_Y[X]/[Y]X/Y
derivative_of_X_wrt_Y[X]/[Y]dX/dY
correlation_over_Z_of_X_and_Y1correlation coefficient for variations over Z (e.g. time, longitude) of X and Y
covariance_over_Z_of_X_and_Y[X]*[Y]covariance for variations over Z (e.g. time, longitude) of X and Y
histogram_over_Z_of_X1histogram (i.e. number of counts for each range of X) of variations over Z of X
probability_distribution_over_Z_of_X1probability distribution (i.e. a number in the range 0.0-1.0 for each range of X) of variations over Z of X
probability_density_function_over_Z_of_X1/[X]PDF for variations over Z of X

For the histogram, probability distribution and probability density function, the data variable would be expected to have an axis for X.

Standard name table

unitsGRIBstashAMIPstandard_name: clarification
Papressure
Pastress: momentum flux density, a tensor, component pair order Z Y X, if only one then magnitude
kgmass
m2area
m3volume
Ktemperature
mthickness: vertical extent of a layer
mheight: above surface i.e. how tall something is
m8altitude: above geoid, the reference geopotential surface, similar to MSL but not identical
mdepth: below surface
1mass_fraction: of X in Y
1mass_mixing ratio: of X with Y
1volume_fraction: of X in Y
1area_fraction: of X means the fraction of horizontal area occupied by X
W m-2heat_flux_density
Wheat_flux
Wpower
kg m-2 s-1mass_flux_density
kg s-1mass_flux
m s-1volume_flux_density
m3 s-1volume_flux
Jenergy
J m-2energy_content
J m-3energy_density
kg m-2content: W X content, where W is one word, means the X content of W
kg m-2amount
m s-1speed: magnitude of velocity
m s-1velocity: vector quantity
kgmass
stime: in NWP = validity time, valid time, analysis time
speriod: interval of time, or time period of oscillation
kg m-389density
degrees_Elongitude
degrees_Nlatitude
1binary_mask: X_binary_mask has 1 where condition X is met, 0 elsewhere
1data_mask: X_data_mask has non-missing data (value irrevelant) where condition X is met, missing data elsewhere
s-1frequency
s-1frequency of occurrence: of X, where X is some event
1probability: of X, chance of condition X being true or of at least one occurrence of event X
1sigma: ratio of pressure to surface pressure
1hybrid_sigma_pressure: vertical coordinate, see appendix
1sigma_term_in_hybrid_sigma_pressure: "b" component of hybrid sigma-pressure coordinate
1pressure_fraction_term_in_hybrid_sigma_pressure: "a" component of hybrid sigma-pressure divided by std p
Papressure_term_in_hybrid_sigma_pressure: "a" component of hybrid sigma-pressure
mhybrid_height
1height_term_in_hybrid_height
1altitude_term_in_hybrid_height
1model_level_number: to be understood as equivalent to layer number
sforecast_reference_time: in NWP = data time, time of analysis from which forecast was made
sforecast_period: time interval between forecast_reference_time and validity time
m2 s-2enekspecific_eddy_kinetic_energy
msea_floor_depth
Papartial_pressure
Pa1pssurface_air_pressure
Pa1air_pressure
Pa26air_pressure_anomaly
Pa s-13rate_of_change_of_air_pressure
kg m-3air_density
kg m-3sea_water_density
kg m-3sea_water_potential_density: referred to the surface
m s-132wind_speed: magnitude of wind velocity
m s-1332uaeastward_wind
m s-1343vanorthward_wind
degree31wind_direction
m s-133grid_eastward_wind
m s-134grid_northward_wind
K134air_potential_temperature
kg m-2869mrso?soil_water_content
15110husspecific_humidity: mass fraction of water vapour in moist air
111mass_fraction_of_water_in_air
171clcloud_area_fraction: fraction of area which contains cloud, cloud amount, cloud cover
17213convective_cloud_area_fraction
173low_cloud_area_fraction
174medium_cloud_area_fraction
175high_cloud_area_fraction
maltitude_at_cloud_base
Paair_pressure_at_cloud_base
maltitude_at_cloud_top
Paair_pressure_at_cloud_top
kg m-276cloud_condensed_water_content: liquid and solid
kg m-254prwatmosphere_water_content: precipitable water ???
K8520soil_temperature: bulk temperature, not surface
kg m-222canopy_water_amount: on the vegetation, not on the ground
mLWE_thickness_of_canopy_water_amount
kg m-26523snw?surface_snow_amount: on the ground i.e. not canopy
m66sndsurface_snow_thickness
mLWE_thickness_of_surface_snow_amount
1sncsurface_snow_area_fraction
K24tssurface_temperature: temperature at the interface, not bulk temperature of the top layer
m25zblaatmosphere_boundary_layer_thickness
m8326surface_roughness_length
m s-14928eastward_sea_water_velocity
m s-15029northward_sea_water_velocity
m s-148sea_water_speed: magnitude of velocity
degree47direction_of_sea_water_velocity
130land_binary_mask: 1 = land, 0 = sea
19131sicsea_ice_area_fraction: areal fraction of sea-ice
m9232sea_ice_thickness
kg m-2sea_ice_amount
kgsea_ice_mass
m2sea_ice_area
m2sea_ice_extent
m3sea_ice_volume
msea_ice_freeboard: height of sea-ice upper surface above water surface
msea_ice_draft: depth of sea-ice lower surface below water surface
m33orogsurface_altitude
Ksurface_temperature_anomaly
mLWE_thickness_of_soil_water_content: ??? vol smc
kg m-2mrsofcsoil_water_content_at_field_capacity
1mrsotbratio_of_soil_water_content_to_soil_water_content_at_field_capacity: ??? snappier name
18750vegetation_area_fraction
m51root_depth: maximum depth of soil reached by plant roots
184surface_albedo
1surface_albedo_assuming_no_snow
1surface_albedo_assuming_deep_snow
160mass_fraction_of_O3_in_air
1tro3?molar_fraction_of_O3_in_air: ??? eqv to vol fraction
m s-140150upward_wind
s-138150upward_wind_expressed_as_rate_of_change_of_sigma
kg m-2160atmosphere_SO4_content
181205sftlfland_area_fraction
1sea_area_fraction
1sftgifland_ice_area_fraction: glaciers, ice caps and ice sheets
1leaf_area_index
mcanopy_height: vegetation canopy
1214mass_fraction_of_unfrozen_water_in_soil_water
1215mass_fraction_of_frozen_water_in_soil_water
kg m-2mrfsosoil_frozen_water_content
1220soil_albedo: assuming no snow
kg m-2221snow_soot_content ????
J m-2atmosphere_energy_content
kg m-2223soil_carbon_content
m231snow_grain_size
K233snow_temperature: bulk temperature, not surface
K11taair_temperature: bulk temperature, not surface; in-situ, not potential
K25air_temperature_anomaly
W m-2rtmtTOA_downward_radiative_heat_flux_density: shortwave+longwave ??? mt
W m-21111201rsnssurface_downward_shortwave_heat_flux_density: solar wavelengths, net i.e. incident minus reflected
W m-2116downward_shortwave_heat_flux_density: net, within atmosphere
W m-2115downward_longwave_heat_flux_density: net, within atmosphere
W m-2113rsdtTOA_downward_shortwave_heat_flux_density: net
W m-21207rsdtTOA_incoming_shortwave_heat_flux_density: heat flux from the sun
W m-21208rsutTOA_outgoing_shortwave_heat_flux_density: reflected and scattered solar heat flux, all sky
W m-21209rsutcsTOA_outgoing_shortwave_heat_flux_density_assuming_clear_sky
W m-21210rsdscssurface_incident_shortwave_heat_flux_density_assuming_clear_sky
W m-21211rsuscssurface_reflected_shortwave_heat_flux_density_assuming_clear_sky: i.e. not absorbed
W m-2rsussurface_reflected_shortwave_heat_flux_density: i.e. not absorbed
1large_scale_cloud_area_fraction
K s-11232rate_of_change_of_air_temperature_due_to_shortwave_heating
K s-11233rate_of_change_of_air_temperature_due_to_shortwave_heating_assuming_clear_sky
W m-21171235rsdssurface_incident_shortwave_heat_flux_density: global radiation, direct and diffuse
W m-21237tropopause_downward_shortwave_heat_flux_density: net
W m-21238tropopause_upward_shortwave_heat_flux_density_from_below: flux from downward-looking hemisphere
W m-22201rlnssurface_downward_longwave_heat_flux_density: net
W m-2rlussurface_emitted_longwave_heat_flux_density
W m-2rluscssurface_emitted_longwave_heat_flux_density_assuming_clear_sky
W m-22205rlutTOA_upward_longwave_heat_flux_density: OLR
W m-2114TOA_downward_longwave_heat_flux_density: -OLR
W m-22206rlutcsTOA_upward_longwave_heat_flux_density_assuming_clear_sky
W m-22207rldssurface_incident_longwave_heat_flux_density
W m-22208rldscssurface_incident_longwave_heat_flux_density_assuming_clear_sky
K s-12232tntlwrate_of_change_of_air_temperature_due_to_longwave_heating
K s-12233rate_of_change_of_air_temperature_due_to_longwave_heating_assuming_clear_sky
W m-22237tropopause_downward_longwave_heat_flux_density: net
W m-22238tropopause_downward_longwave_heat_flux_density_from_above: flux from downward-looking hemisphere
W m-23201downward_heat_flux_density_in_sea_ice
W m-23202downward_heat_flux_density_in_soil
13203drag_coefficient
s-13205derivative_of_wind_speed_wrt_altitude_in_constant_flux_layer
Pa3206downward_stress_in_constant_flux_layer: magnitude of momentum, not direction, within layer, not surface
13208bulk_Richardson_number
W m-23217upward_sensible_heat_flux_density_in_air ???? constant flux layer
Pa1243219downward_eastward_stress_in_air: above surface "
Pa1253220downward_northward_stress_in_air: above surface "
kg m-2 s-13223upward_water_vapour_mass_flux_density_in_air "
W m-21263224wind_mixing_energy_flux_density_into_sea
W m-2hfsssurface_upward_sensible_heat_flux_density
W m-2122surface_downward_sensible_heat_flux_density
W m-23228surface_upward_sensible_heat_flux_density_from_sea
kg m-2 s-1evspsblsurface_upward_water_vapour_mass_flux_density: net mass rate of evaporation plus sublimation
W m-23234hflssurface_upward_latent_heat_flux_density: same sign as water vapour flux
W m-2121surface_downward_latent_heat_flux_density: opppsite sign to water vapour flux
1climass_fraction_of_cloud_ice_in_air
kg m-258cliviatmosphere_cloud_ice_content
1clwmass_fraction_of_cloud_liquid_water_in_air
kg m-2clwviatmosphere_cloud_liquid_water_content
m20visibility: distance at which something can be seen
K17dew_point_temperature
Kfreezing_temperature_of_sea_water
kg m-299snmsurface_snow_melt_amount: ???? is that really what AMIP wants?
W m-23258surface_snow_melt_heat_flux_density: supply of latent heat melting snow at freezing point
kg m-23260transpiration_amount
kg m-2 s-1transpiration_mass_flux_density
kg m-2 s-13261gross_primary_productivity_of_carbon_amount
kg m-2 s-13262net_primary_productivity_of_carbon_amount
kg m-2 s-13263plant_respiration_mass_flux_density ??? is this a carbon amount
kg m-24201large_scale_rainfall_amount
kg m-2794202large_scale_snowfall_amount
kg m-2 s-14303large_scale_rainfall_mass_flux_density
kg m-2 s-14304large_scale_snowfall_mass_flux_density
152hurrelative_humidity
kg m-25201convective_rainfall_amount
kg m-2785202convective_snowfall_amount
s-1tnmrcrate_of_change_of_specific_humidity_due_to_convection
kg m-2 s-15205convective_rainfall_mass_flux_density
kg m-2 s-15206convective_snowfall_mass_flux_density
Pa5207air_pressure_at_convective_cloud_base
Pa5208air_pressure_at_convective_cloud_top
15213mass_fraction_of_convective_condensed_water_in_air
kg m-2 s-15214rainfall_mass_flux_density
kg m-2 s-1645215prsnsnowfall_mass_flux_density
kg m-2 s-1595216prprecipitation_mass_flux_density
J kg-1specific_potential_energy
J kg-1specific_convectively_available_potential_energy: CAPE
kg m-2615226precipitation_amount
kg m-262large_scale_precipitation_amount
kg m-263convective_precipitation_amount
kg m-2 s-1prcconvective_precipitation_mass_flux_density
m s-2tnmmcrate_of_change_of_wind_due_to_convention: magnitude, not directiom
s-1tnmrdrate_of_change_of_specific_humidity_due_to_diabatic_processes
s-1tntrate_of_change_of_air_temperature_due_to_diabatic_processes
s-1tntlsprate_of_change_of_air_temperature_due_to_large_scale_precipitation
s-1tntmcrate_of_change_of_air_temperature_due_to_moist_convection
s-1tntdcrate_of_change_of_air_temperature_due_to_dry_convection
Pa6201tauugwdsurface_eastward_gravity_wave_stress: is 6201 surface? is it a wind stress?
Pa6202tauvgwdsurface_northward_gravity_wave_stress: is 6202 surface? is it a wind stress?
m s-2tnmmgwdrate_of_change_of_wind_due_to_gravity_wave_drag
m s-2tnmmgwdurate_of_change_of_eastward_wind_due_to_gravity_wave_drag
m s-2tnmmgwdvrate_of_change_of_northward_wind_due_to_gravity_wave_drag
kg m-2908204surface_runoff_amount
kg m-28204subsurface_runoff_amount
kg m-2 s-1mrrossurface_runoff_mass_flux_density
kg m-2 s-1subsurface_runoff_mass_flux_density
kg m-2 s-1mrrorunoff_mass_flux_density: surface plus subsurface runoff
K9222wet_bulb_temperature
Pa s-13912201wapomega: downward wind using pressure as the vertical component
K m2 kg-1 s-115214Ertel_potential_vorticity
m2 s-215215mpuvaproduct_of_eastward_wind_and_northward_wind
K m s-115217product_of_air_temperature_and_eastwind_wind
K m s-115218mpvtaproduct_of_air_temperature_and_northward_wind
K215219mpttasquare_of_air_temperature
m2 s-215220mpuuasquare_of_eastward_wind
m2 s-215221mpvvasquare_of_northward_wind
Pa m s-215224product_of_eastward_wind_and_omega
Pa m s-215225product_of_northward_wind_and_omega
m s-115227product_of_eastward_wind_and_specific_humidity
m s-115228mpvhusaproduct_of_northward_wind_and_specific_humidity
K Pa s-115235mpwhusaproduct_of_air_temperature_and_omega: assume w is omega ???
J m-215237atmosphere_kinetic_energy_content
m715238zggeopotential_height
m27geopotential_height_anomaly
m2 s-115239product_of_eastward_wind_and_geopotential_height
m2 s-115240mpvzgaproduct_of_northward_wind_and_geopotential_height
m16210freezing_level_altitude
Pa16211freezing_level_air_pressure
Pa16214tropopause_air_pressure
K16215tropopause_air_temperature
m16216tropopause_altitude
Pa216222pslsea_level_air_pressure: mslp
kg m-219002vegetation_carbon_content
kg m-2 s-119005litter_carbon_mass_flux_density
K80optsea_water_temperature
K101optsea_water_potential_temperature: referred to surface
188102sea_water_salinity: ??? should PSU be a new unit
m s-1121baroclinic_eastward_sea_water_velocity
m s-1122baroclinic_northward_sea_water_velocity
m3 s-1130ocean_barotropic_streamfunction
m3 s-2132rate_of_change_of_ocean_barotropic_streamfunction
m134ssesea_surface_elevation: above geoid i.e. altitude
m82sea_surface_elevation_anomaly
m s-1135barotropic_eastward_sea_water_velocity
m s-1136barotropic_northward_sea_water_velocity
m67137ocean_mixed_layer_thickness
Pa139eastward_stress_of_sea_ice_on_ocean
Pa140northward_stress_of_sea_ice_on_ocean
m141surface_snow_thickness_on_sea_ice
W m-2143upward_sensible_heat_flux_density_in_sea_water_at_sea_ice_base: basal heat flux
m s-194sea_ice_speed
m s-195148sea_ice_eastward_velocity
m s-196149sea_ice_northward_velocity
degree93direction_of_sea_ice_velocity
s-198divergence_of_sea_ice_velocity
m s-197rate_of_change_of_sea_ice_thickness_due_to_thermodynamics
Pa150tauusurface_downward_eastward_stress
Pa151tauvsurface_downward_northward_stress
W m-2185heat_flux_correction
kg m-2 s-1186water_flux_correction
m2 s-1194ocean_isopycnal_layer_thickness_diffusivity
m s-130201sea_water_upward_velocity
W30211northward_heat_flux_in_ocean
kg s-130212northward_salt_mass_flux_in_ocean
kg s-1northward_fresh_water_mass_flux_in_ocean
m100significant_height_of_wind_waves_and_swell_waves: on the ocean surface
degree101direction_of_wind_wave_velocity
m102significant_height_of_wind_waves
s103wind_wave_period
degree104direction_of_swell_wave_velocity
m105significant_height_of_swell_waves
s106swell_wave_period