GRIB Edition 1: WMO Code Table 2

WMO Code table 2 - Indicator of parameter

Code figure	Field parameter	Unit
000	Reserved
001	Pressure	Pa
002	Pressure reduced to MSL	Pa
003	Pressure tendency	Pa s^-1
004	Potential vorticity	K m² kg^-1 s^-1
005	ICAO Standard Atmosphere reference height	m
006	Geopotential	m² s^-2
007	Geopotential height	gpm
008	Geometrical height	m
009	Standard deviation of height	m
010	Total ozone	Dobson
011	Temperature	K
012	Virtual temperature	K
013	Potential temperature	K
014	Pseudo-adiabatic potential temperature	K
015	Maximum temperature	K
016	Minimum temperature	K
017	Dew-point temperature	K
018	Dew-point depression (or deficit)	K
019	Lapse rate	K m^-1
020	Visibility	m
021	Radar spectra (1)	-
022	Radar spectra (2)	-
023	Radar spectra (3)	-
024	Parcel lifted index (to 500 hPa) (see Note 6)	K
025	Temperature anomaly	K
026	Pressure anomaly	Pa
027	Geopotential height anomaly	gpm
028	Wave spectra (1)	-
029	Wave spectra (2)	-
030	Wave spectra (3)	-
031	Wind direction	Degree true
032	Wind speed	m s^-1
033	u-component of wind (see Note 4)	m s^-1
034	v-component of wind (see Note 4)	m s^-1
035	Stream function	m² s^-1
036	Velocity potential	m² s^-1
037	Montgomery stream function	m² s^-1
038	Sigma coordinate vertical velocity	s^-1
039	Vertical velocity	Pa s^-1
040	Vertical velocity	m s^-1
041	Absolute vorticity	s^-1
042	Absolute divergence	s^-1
043	Relative vorticity	s^-1
044	Relative divergence	s^-1
045	Vertical u-component shear (see Note 4)	s^-1
046	Vertical v-component shear (see Note 4)	s^-1
047	Direction of current	Degree true
048	Speed of current	m s^-1
049	u-component of current (see Note 4)	m s^-1
050	v-component of current (see Note 4)	m s^-1
051	Specific humidity	kg kg^-1
052	Relative humidity	%
053	Humidity mixing ratio	kg kg^-1
054	Precipitable water	kg m^-2
055	Vapor pressure	Pa
056	Saturation deficit	Pa
057	Evaporation	kg m^-2
058	Cloud ice	kg m^-2
059	Precipitation rate	kg m^-2 s^-1
060	Thunderstorm probability	%
061	Total precipitation	kg m^-2
062	Large scale precipitation	kg m^-2
063	Convective precipitation	kg m^-2
064	Snowfall rate water equivalent	kg m^-2 s^-1
065	Water equivalent of accumulated snow depth	kg m^-2
066	Snow depth	m
067	Mixed layer depth	m
068	Transient thermocline depth	m
069	Main thermocline depth	m
070	Main thermocline anomaly	m
071	Total cloud cover	%
072	Convective cloud cover	%
073	Low cloud cover	%
074	Medium cloud cover	%
075	High cloud cover	%
076	Cloud water	kg m^-2
077	Best lifted index (to 500 hPa) (see Note 6)	K
078	Convective snow	kg m^-2
079	Large scale snow	kg m^-2
080	Water temperature	K
081	Land cover (1 = land, 0 = sea)	Proportion
082	Deviation of sea level from mean	m
083	Surface roughness	m
084	Albedo	%
085	Soil temperature	K
086	Soil moisture content	kg m^-2
087	Vegetation	%
088	Salinity	kg kg^-1
089	Density	kg m^-3
090	Water run-off	kg m^-2
091	Ice cover (1 = ice, 0 = no ice)	Proportion
092	Ice thickness	m
093	Direction of ice drift	Degree true
094	Speed of ice drift	m s^-1
095	u-component of ice drift (see Note 4)	m s^-1
096	v-component of ice drift (see Note 4)	m s^-1
097	Ice growth rate	m s^-1
098	Ice divergence	s^-1
099	Snow melt	kg m^-2
100	Significant height of combined wind waves and swell	m
101	Direction of wind waves	Degree true
102	Significant height of wind waves	m
103	Mean period of wind waves	s
104	Direction of swell waves	Degree true
105	Significant height of swell waves	m
106	Mean period of swell waves	s
107	Primary wave direction	Degree true
108	Primary wave mean period	s
109	Secondary wave direction	Degree true
110	Secondary wave mean period	s
111	Net short-wave radiation flux (surface) (see Note 3)	W m^-2
112	Net long-wave radiation flux (surface) (see Note 3)	W m^-2
113	Net short-wave radiation flux (top of atmosphere) (see Note 3)	W m^-2
114	Net long-wave radiation flux (top of atmosphere) (see Note 3)	W m^-2
115	Long-wave radiation flux (see Note 3)	W m^-2
116	Short-wave radiation flux (see Note 3)	W m^-2
117	Global radiation flux (see Note 3)	W m^-2
118	Brightness temperature	K
119	Radiance (with respect to wave number)	W m^-1 sr^-1
120	Radiance (with respect to wave length)	W m^-3 sr^-1
121	Latent heat flux	W m^-2
122	Sensible heat flux	W m^-2
123	Boundary layer dissipation	W m^-2
124	Momentum flux, u-component (see Note 4)	N m^-2
125	Momentum flux, v-component (see Note 4)	N m^-2
126	Wind mixing energy	J
127	Image data
128-254	Reserved for originating center use
255	Missing value

SI units only are used for GRIB; the accuracy or precision with which the data are represented is a function of the range of values, the decimal and/or binary scaling, and the number of bits used; GRIB enables suitable scaling factors to be selected to obviate the need to define parameters in non-SI units.
The code figures 0 to 127 are used to represent parameters which are exchanged between a number of centers; since the products generated by centers can be extremely diverse, code figures 128 to 254 are reserved for definition by the originating center and may differ from center to center.
By convention, downward fluxes of radiation or other quantities shall be assigned negative values; upward fluxes of radiation or other quantites shall be assigned positive values.
The u- and v-components of vector quantities are defined in Code table 7.
Provision is made for three types of spectra:
1. direction and frequency;
2. direction and radial number;
3. radial number and radial number.
The "parcel lifted index" (as defined in the International Meteorology Vocabulary (WMO-No. 182) under the listing "lifted index") is defined as the temperature difference between the ambient 500 hPa temperature (T500) and that of a parcel of air lifted from the surface (Tparcel) following the dry and moist adiabatic process. Negative values of (T500 - Tparcel) suggest instability. The "best lifted index" is defined as the most unstable of a collection of parcel lifted indices, with parcel initial conditions defined for a collection of 30 hPa thick layers stacked one upon the other with the lowest resting on the ground. Commonly, four to six such layers are used in the calculation.