GRIB-API definition

NameSkin temperatureAbbreviationsktUnitKparamId235
DefinitionTemperature of of an infinitesimally thin surface layer of land or water surface at radiative equilibrium.
Validityinstantaneous
Comment 

 

GRIB2 definition

Parameter
Discipline0meteorological products
Parameter Category0temperature
Parameter Number17skin temperature
Level
Type of first fixed surface1ground or water surface
Scale factor of first fixed surfaceall bits to 1missing
Scaled value of first fixed surfaceall bits to 1missing
Type of second fixed surfaceall bits to 1
missing
Scale factor of second fixed surfaceall bits to 1missing
Scaled value of second fixed surfaceall bits to 1missing

4 Comments

  1. Richard Mladek

    Further specification needed.

  2. Per Unden

    Temperature of an infinitesimally thin surface layer of land or water corresponding to the kinetic energy of the matter.

  3. Gianpaolo Balsamo

    The skin temperature SKT is a temperature in radiative equilibrium and is globally defined (land and water point) but it is instantaneous and has no memory. This is interesting because it shall be the temperature comparable to a satellite skin temperature.

    An ECMWF-IFS alternative that has memory and it is an actual prognostic is the STL1 grib code, which is the top soil temperature (representative of 0 to 7 cm depth). STL1 over water is equal to SSTK and over ice is equal to ISTL1 (the top layer ice temperature), therefore it is also globally defined. However it is just used in GRIB1 and not a WMO defined GRIB2.

    An alternative would be to consult S2S parameters, which were defined with purpose of finding common intercomparable quantities, see:
    List of S2S parameters.

    It is very likely that this quantity will remain model-dependent as there is a variety of modelling assumption concerning the way soil vertical discretisation and root distribution are represented in models.

     

  4. Per Unden

    I think we settle for Skin temperature as Surface temperature is ill defined.