GRIB-API definition
Name | Soil temperature | Abbreviation | sot | Unit | K | paramId: | 260360 |
UERRA details
Definition | Temperature of a soil level (or layer for MetOffice). |
Validity | instantaneous |
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 | ||
---|---|---|
Discipline | 2 | land surface products |
Parameter category | 3 | soil products |
Parameter number | 18 | soil temperature |
Definition for soil levels 1...X:
Level | ||
---|---|---|
Type of first fixed surface | 151 | soil level** |
Scale factor of first fixed surface | 0 | |
Scaled value of first fixed surface | 1/2/3/.../X | n for the nth soil level |
Type of second fixed surface | all bits to 1 | missing |
Scale factor of second fixed surface | all bits to 1 | missing |
Scaled value of second fixed surface | all bits to 1 | missing |
Definition for soil layers 1...X:
Level | ||
---|---|---|
Type of first fixed surface | 151 | soil level** |
Scale factor of first fixed surface | 0 | |
Scaled value of first fixed surface | 0/1/2/3/.../X-1 | n-1 for the nth soil layer |
Type of second fixed surface | 151 | soil level* |
Scale factor of second fixed surface | 0 | |
Scaled value of second fixed surface | 1/2/3/.../X | n for the nth soil layer |
**newly approved level type (WMO release in May 2016)
11 Comments
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.
Richard Mladek
There is "soil temperature" (parameter number 2) defined also under parameter category 0: vegetation/biomass but it is deprecated now.
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.
Richard Mladek
Further discussion and investigation is needed:
Richard Mladek
Related links:
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
to be consistent with newly defined soil heat flux etc.
Sebastien Villaume
do you mean we need to propose a new parameter?
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
francois besson
Hello,
In the table "Definition for soil level" the following row may not be correct
It should be :
Do you agree ?
Best regards
François
Richard Mladek
Yes of course. Sorry for that half updated page in the past.
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).