Below is a list of all agreed upon parameters. Participating Centers are expected to produce output fields in GRIB2 data format and with consistent units. All units are defined by the WMO in the GRIB2 manual . For more information please refer to Guide to the WMO Table Driven Code Form.

  • Rules for parameter exchanges and GRIB2 encoding can be found here.
  • List of parameters provided by each partner for S2S archive is available here.

List of parameters

Pressure level parameters

The following parameters are available on ten pressure levels (1000, 925, 850, 700, 500, 300, 200, 100, 50 and 10  hPa)

(during 2016-7 the vertical velocity will be added to all pressure levels by providers in their earliest convenience)

NameAbbreviationUnit Frequency
Geopotential heightghgpmInstantaneous once a day (00Z)
TemperaturetKInstantaneous once a day (00Z)
U-velocityum s-1Instantaneous once a day (00Z)
V-velocityvm s-1Instantaneous once a day (00Z)
Vertical velocitywpa s-1Instantaneous once a day (00Z)

The following parameters are available on seven pressure levels (1000, 925, 850, 700, 500, 300 and  200 hPa)

Name                     Abbreviation  Unit   Frequency
Specific humidityqkg kg-1Instantaneous once a day (00Z)

The following parameter are available on 1 pressure level (500 hPa)

(during 2016-7 the vertical velocity will be added to all pressure levels by providers in their earliest convenience)

Name                     AbbreviationUnit     Frequency
Vertical velocitywpa s-1Instantaneous once a day (00Z)

Potential temperature level parameters

The following parameters are available on one potential temperature level  (320 K)

NameAbbreviationUnitFrequency
Potential vorticitypvK m2 kg-1 s-1Instantaneous once a day (00Z)

Single-level parameters

The following parameters are available on single levels

NameAbbreviationUnitFrequency
10 metre u-velocity10um s-1

Instantaneous once a day (00Z)

6-hourly where possible (new request since 2020)

10 metre v-velocity10vm s-1

Instantaneous once a day (00Z)

6-hourly where possible (new request since 2020)

CAPEcapeJ kg-1Daily averaged
Skin temperaturesktKDaily averaged
Snow depth water equivalentsdkg m-2Daily averaged
Snow density          
rsnkg m-3Daily averaged
Snow fall water equivalentsfkg m-2

Accumulated, archived every 24 hours

Snow albedo          
asn%Daily averaged
Soil moisture top 20 cmsm20
kg m-3Daily averaged
Soil moisture top 100 cmsm100kg m-3Daily averaged
Soil temperature top 20 cmst20KDaily averaged
Soil temperature top 100 cmst100KDaily averaged
Surface air maximum temperaturemx2t6K6-hourly
Surface air minimum temperaturemn2t6K6-hourly
Surface air temperature2tKDaily averaged
Surface air dewpoint temperature2d2dDaily averaged
Sea surface temperature  
wtmpKDaily averaged
Sea ice cover  ciproportionDaily averaged
Surface pressurespPaInstantaneous once a day (00Z)
Time-integrated top net thermal radiationttrW m-2 sAccumulated, archived every 24 hours
Time-integrated surface latent heat fluxslhfW m-2 sAccumulated, archived every 24 hours
Time-integrated surface net solar radiationssrW m-2 sAccumulated, archived every 24 hours
Time-integrated surface net thermal radiationstrW m-2 sAccumulated, archived every 24 hours
Time-integrated surface sensible heat fluxsshfW m-2 sAccumulated, archived every 24 hours
Time-integrated surface solar radiation downwardsssrd W m-2 sAccumulated, archived every 24 hours
Time-integrated surface thermal radiation downwardsstrdW m-2 sAccumulated, archived every 24 hours
Total cloud covertcc%Daily averaged
Total column watertcwkg m-2Daily averaged
Total precipitationtpkg m-2Accumulated, 6-hourly 
Convective precipitation 
cpkg m-2Accumulated, archived every 24 hours
Northward turbulent surface stress 
nsssN m-2 sAccumulated, archived every 24 hours
Eastward turbulent surface stress ewssN m-2 sAccumulated, archived every 24 hours
Mean sea-level pressuremslPaInstantaneous once a day (00Z)
Water runoff and drainage 
rokg m-2Accumulated, archived every 24 hours
Surface water runoff 
srokg m-2Accumulated, archived every 24 hours
Land sea masklsmProportion of land

Instantaneous once a day (00Z)

Only control forecast

Orographyoroggpm

Instantaneous once a day (00Z)

Only control forecast

Soil type  sltCategorical

Instantaneous once a day (00Z)

Only control forecast

Ocean parameters

The following parameters coming from ocean part of modelling system are available on single levels

NameAbbreviationUnitFrequency
Depth of 20 C isothermt20dmDaily averaged
Mean sea water practical salinity in the  upper 300 msav300psu (numeric)Daily averaged
Mean sea water potential temperature in the upper 300 mmswpt300KDaily averaged
Ocean mixed layer thickness defined by sigma theta 0.01 kg/m3mlotst010mDaily averaged
U-component of surface currentocum s-1Daily averaged
V-component of surface currentocvm s-1Daily averaged
Sea-ice thicknesssithickmDaily averaged
Sea surface heightzosmDaily averaged
Sea surface practical salinitysospsu (numeric)Daily averaged