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
Climate and Forecast (CF) standard names parameter vocabulary
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.
"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.
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.
"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.
"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.
"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.
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.
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.
Sea surface wave variance spectral density is the variance of wave amplitude within a range of wave frequency.
"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.
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.
"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.
Mole fraction is used in the construction mole_fraction_of_X_in_Y, where X is a material constituent of 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.)
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.
"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.
"direction_of_X" means direction of a vector, a bearing. A velocity is a vector quantity.
Standard names for platform describe the motion and orientation of the vehicle from which observations are made e.g. aeroplane or ship.
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.
"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.
"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.
"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.
The surface called "surface" means the lower boundary of the atmosphere.
"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.
"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.
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.
"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.
"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".
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.
Instantaneous forcing is the radiative flux change caused instantaneously by an imposed change in radiative forcing agent (greenhouse gases, aerosol, solar radiation, etc.).
"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.
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.
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.
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.
Model level number should be understood as equivalent to layer 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.
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.
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.
"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.
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.)
"Volume fraction" is used in the construction volume_fraction_of_X_in_Y, where X is a material constituent of Y.
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.
Height is the vertical distance above the surface. Swell waves are waves on the ocean surface.
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.
"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.
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.
The radiation wavelength can refer to any electromagnetic wave, such as light, heat radiation and radio waves.
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.
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.
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.
"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).
"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.
"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.
Solar zenith angle is the the angle between the line of sight to the sun and the local vertical.
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.
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".
"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.
Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy.
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.
"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.
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.
"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.
"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.
"Aerosol" means the suspended liquid or solid particles in air (except cloud droplets).
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.
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.
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).
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.
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.
"Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock.
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".
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.
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.
"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.
cloud_base refers to the base of the lowest cloud. Convective cloud is that produced by the convection schemes in an atmosphere model.
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.
"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.
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.
"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.
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.
Altitude is the (geometric) height above the geoid, which is the reference geopotential surface. The geoid is similar to mean sea level.
Fractional saturation is the ratio of some measure of concentration to the saturated value of the same quantity.
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).
"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.
"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.
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.
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.
"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).
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.
The surface called "surface" means the lower boundary of the atmosphere. "Amount" means mass per unit area.
"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.
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.
moles_of_X_per_unit_mass_inY is also called "molality" of X in Y, where X is a material constituent of Y.
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.
"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.)
"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.
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.
See Appendix D of the CF convention for information about dimensionless vertical coordinates.
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.
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.
"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.
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.
"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.
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).
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.
"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.
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.
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).
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.
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.
A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward).
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.
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.
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.
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.
"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.
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.)
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.
"ln_X" means natural logarithm of X. X must be dimensionless. See Appendix D of the CF convention for information about dimensionless vertical coordinates.
A variable with the standard name of region contains strings which indicate geographical regions. These strings must be chosen from the standard region list.
"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.
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.
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.
"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.
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.
"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.
"to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed.
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 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.
"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.
Sound pressure is the difference from the local ambient pressure caused by a sound wave at a particular location and time.
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.
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.
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.
Dew point temperature is the temperature at which a parcel of air reaches saturation upon being cooled at constant pressure and specific humidity.
Potential temperature is the temperature a parcel of air or sea water would have if moved adiabatically to sea level pressure.
"Content" indicates a quantity per unit area. "Vegetation" means any plants e.g. trees, shrubs, grass.
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.
"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".
"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.
Snow temperature is the bulk temperature of the snow, not the surface (skin) temperature.
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.
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.
"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.
In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics.
"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.
"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.
Height is the vertical distance above the surface.
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.
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.
"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".)
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.
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.
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.
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.
"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.
"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.
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.
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.
The scattering angle is that between the direction of the beam of incident radiation and the direction into which it is scattered.
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.
Solar elevation angle is the angle between the line of sight to the sun and the local horizontal.
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.
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).
"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.
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.
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.
"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.
"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.
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).
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.
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.
Sea ice freeboard is the height of the sea-ice upper surface above the water surface.
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.
"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).
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.
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.
"anomaly" means difference from climatology.
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. The equivalent pressure of a particular constituent of the atmosphere is the surface pressure exerted by the weight of that constituent alone.
"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.
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.
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.
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.
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.
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.
"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.
"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.)
The visibility is the distance at which something can be seen.
"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.)
"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.
"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.
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).
"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 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.
"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).
"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.
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.
"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.)
"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.
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.
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.
"X_area" means the horizontal area occupied by X within the grid cell.
"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.
"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.
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.)
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.
"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.
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.
"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.)
Realization is used to label a dimension that can be thought of asa statistical sample, e.g., labelling members of a model ensemble.
"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.
"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.
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.
"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.)
"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.
A velocity is a vector quantity. "Horizontal" indicates that the velocity potential applies to a horizontal velocity field on a particular vertical level.
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.
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.
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.
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.
"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.
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).
"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.
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.
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.
"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.
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.
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.
"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.
"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.
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.
"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.
"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.
"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.
"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.
"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.
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.
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.
"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.
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).
X_binary_mask has 1 where condition X is met, 0 elsewhere. 1 = land, 0 = sea.
"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.).
"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.
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.
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.
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.
Humidity mixing ratio of a parcel of moist air is the ratio of the mass of water vapor to the mass of dry 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.) In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics.
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.
"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).
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.
cloud_base refers to the base of the lowest cloud.
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.
The ocean meridional overturning streamfunction should not include not include "bolus" or Gent-McWilliams velocity.
"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.
"longwave" means longwave radiation. Net absorbed radiation is the difference between absorbed and emitted radiation.
"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.
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".
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.
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.
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.
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.)
Frequency is the number of oscillations of a wave per unit time.
"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.
"anomaly" means difference from climatology. Air temperature is the bulk temperature of the air, not the surface (skin) temperature.
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.
"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.
"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.
"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.
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.
"tendency_of_X" means derivative of X with respect to time. "X_area" means the horizontal area occupied by X within the grid cell.
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.
"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.
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.
"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.
"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.
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.
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".
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.
"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.
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.
"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.
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.
"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).
"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.
The atmosphere boundary layer thickness is the "depth" or "height" of the (atmosphere) planetary boundary layer.
"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).
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.
"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.
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.
"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 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.
"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".
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.
"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.
"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).
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.
"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".)
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).
"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.).
"[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.
"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.
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.
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.
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.
"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.
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.
"from_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming.
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).
cloud_top refers to the top of the highest cloud.
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.
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.
Zenith angle is the angle to the local vertical; a value of zero is directly overhead.
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.
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.
"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.
"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.
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.
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.
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.
"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.)
"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.
"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.
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.
"tendency_of_X" means derivative of X with respect to time.
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.
"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.)
"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.
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.
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.
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.
"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.
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.
"shortwave" means shortwave radiation. Net absorbed radiation is the difference between absorbed and emitted radiation.
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.
"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.).
A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward).
"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 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.
"square_of_X" means X*X. Air temperature is the bulk temperature of the air, not the surface (skin) 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.
"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.
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.
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.
"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.
Relative vorticity is the upward component of the vorticity vector i.e. the component which arises from horizontal velocity.
Absolute vorticity is the sum of relative vorticity and the upward component of vorticity due to the Earth's rotation.
"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.
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.
sea_level means mean sea level, which is close to the geoid in sea areas.
"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.
"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.)
"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.).
"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.
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.
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.
cloud_top refers to the top of the highest cloud. Air temperature is the bulk temperature of the air, not the surface (skin) temperature.
"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.
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.
"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.
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.
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.
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.)
"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.
"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.
"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.
"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.
Air temperature is the bulk temperature of the air, not the surface (skin) 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.
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).
"X_volume_fraction" means the fraction of volume occupied by X.
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.
"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).
"Horizontal" indicates that the streamfunction applies to a horizontal velocity field on a particular vertical level.
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.
"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.
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.
Depth is the vertical distance below the surface.
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.
"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.
"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.
A velocity is a vector quantity. "Upward" indicates a vector component which is positive when directed upward (negative downward).
"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.
"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.
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.
"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.
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.
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.
"specific" means per unit mass. Specific humidity is the mass fraction of water vapor in (moist) air.
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.
"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.
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.
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.
Sound intensity is the sound energy per unit time per unit area.
"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.
"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.
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.
"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_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.
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.
"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".)
"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.
"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.
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.
"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.
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.
"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.
"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.
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.
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.
"[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.)
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).
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.
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.
"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.).
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.
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.
"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.
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.
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 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.
"Content" indicates a quantity per unit area.
"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.
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".
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.
"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.
"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.
"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.
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.
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.
"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.
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.
"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_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.
"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 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.
"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.)
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.
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 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.
Height is the vertical distance above the surface. "Canopy" means the plant or vegetation canopy.
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.
"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.)
"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.
"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.
"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).
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.
"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).
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.
"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.)
"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.
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.
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.
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.
Soil temperature is the bulk temperature of the soil, not the surface (skin) 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.
"tendency_of_X" means derivative of X with respect to time. "Land ice" means glaciers, ice-caps and ice-sheets resting on bedrock.
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.
"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".)
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.
"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".
"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.)
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.
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.
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.
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.
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.
"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.
"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.
"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.
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.
"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.
"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.
cloud_top refers to the top of the highest cloud. Convective cloud is that produced by the convection schemes in an atmosphere model.
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.
"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.)
Water vapor saturation deficit is the difference between the saturation water vapor pressure and the actual water vapor pressure.
"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.
"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.
"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.
"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.
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.
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.
"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).
"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.
"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.
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.
"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.
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.
"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.
Sea surface wave directional variance spectral density is the variance of the amplitude of the waves within given ranges of direction and wave frequency.
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.
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.
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.
"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.
The surface called "surface" means the lower boundary of the atmosphere. "tendency_of_X" means derivative of X with respect to time.
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.
"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.
"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.
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.
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.
"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.)
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.
"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.
"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).
"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.
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.
"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.
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.
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.
"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.
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).
"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.
A period is an interval of time, or the time-period of an oscillation. Swell waves are waves on the ocean surface.
"square_of_X" means X*X. Frequency is the number of oscillations of a wave per unit time.
"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).
"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.
"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.
"Content" indicates a quantity per unit area. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets).
The soil porosity is the proportion of its total volume not occupied by soil solids.
"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.
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.
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.
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.)
"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".
cloud_top refers to the top of the highest cloud. Height is the vertical distance above the surface.
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.
Soil albedo is the albedo of the soil surface assuming no snow.
"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.
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.
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.
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.
"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.
"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.)
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.
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.
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.
"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.
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.
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.
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.
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.)
"ratio_of_X_to_Y" means X/Y. "stp" means standard temperature (0 degC) and pressure (101325 Pa).
Sea ice draft is the depth of the sea-ice lower surface below the water surface.
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.
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.
"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.)
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).