GRIB-API definition

NameSoil temperatureAbbreviationsotUnitKparamId:260360

 

UERRA details

DefinitionTemperature of a soil level (or layer for MetOffice).
Validityinstantaneous
Comment

Sea points should be set as missing values (encoded as bitmap). Soil levels/layers must always start from 1 (0 is the surface by default which is not encoded)

 

WMO GRIB2 definition

Parameter
Discipline2land surface products
Parameter category3soil products
Parameter number18soil temperature

Definition for soil levels 1...X:

Level
Type of first fixed surface151soil level**
Scale factor of first fixed surface0 
Scaled value of first fixed surface1/2/3/.../Xn for the nth soil level
Type of second fixed surfaceall bits to 1missing
Scale factor of second fixed surfaceall bits to 1missing
Scaled value of second fixed surfaceall bits to 1missing

Definition for soil layers 1...X:

Level
Type of first fixed surface151soil level**
Scale factor of first fixed surface0 
Scaled value of first fixed surface0/1/2/3/.../X-1n-1 for the nth soil layer
Type of second fixed surface151soil level*
Scale factor of second fixed surface0 
Scaled value of second fixed surface1/2/3/.../Xn for the nth soil layer

**newly approved level type (WMO release in May 2016)

 

11 Comments

  1. Richard Mladek

    Multi-layer definition in MARS

    Example of soil layers in MARS:

    http://apps.ecmwf.int/mars-catalogue/?class=rd&expver=ge8f&stream=oper&type=an&levtype=layer

    The attached st.layers.grib2 contains soil temperature in 6 layers between soil levels 0/1/3/7/15/25cm.

    Update: This comment can be considered as obsolete as the layers are fixed in IFS and this is not generally the case for UERRA products.

  2. Richard Mladek

    There is "soil temperature" (parameter number 2) defined also under parameter category 0: vegetation/biomass but it is deprecated now.

  3. Richard Mladek

    As the soil levels differ generally over UERRA integration domains there is a need for a new WMO soil layer type of level (Code table 4.5–Fixed surface types and units). The UERRA partners would have to provide then also the soil level depths for each grid-point.

  4. Richard Mladek

    Further discussion and investigation is needed:

    • if it is possible to archive it in MARS with Type of first fixed surface = 106 similarly as mentioned in the 1st comment
    • if to ask WMO for new level type soil layer (it is complex problem as the varying soil level depths for each grid-point should have to be encoded as well)

  5. Richard Mladek

    Related links:

  6. Richard Mladek

    Soil temperature GRIB2 paramId

    We use "deprecated" definition http://apps.ecmwf.int/codes/grib/param-db?id=228139

    The proposal it to create a new paramId under

    Discipline2land surface products

    to be consistent with newly defined soil heat flux etc.

     

  7. Sebastien Villaume

    do you mean we need to propose a new parameter?

  8. Richard Mladek

    We should decide if we want to use the already existing one like 228139 or to create a new one with right discipline etc.

    It is listed also in JIRA GRIB-909

  9. francois besson

    Hello,

    In the table "Definition for soil level" the following row  may not be correct

    Scaled value of first fixed surface0/1/2/3n-1 for n-th soil layer

    It should be :

    Scaled value of first fixed surface1/2/3n-th soil level

    Do you agree ?

    Best regards

    François

    1. Richard Mladek

      Yes of course. Sorry for that half updated page in the past.

  10. Sebastien Villaume

    that' s correct, for levels, a value of 0 has no meaning. It is only used for defining layers (where soil level 0 represents the surface).