GRIB-API definition
| Name | Volumetric soil moisture | Abbreviation | vsw | Unit | m3 m-3 | paramId: | 260199 |
UERRA details
| Definition | Volumetric soil moisture of a soil layer. |
| Validity | instantaneous |
| Comment |
Averaged volumetric soil moisture between given levelsSea points should be set as missing values (encoded as bitmap). To interpret soil moisture and to compare different models the Soil Wetness Index (SWI) is used:
SWI = (soil_moisture - wilting_point) / (field_capacity - wilting_point).
Field capacity corresponds to the maximum value that the model can sustain without precipitation for more than a few hours. The vegetated fraction of the soil evaporates at the maximum rate for soil moisture larger than field capacity and stops evaporating below the permanent wilting point, with a continuous variation between the two extremes.
All Partners are asked to provide the wilting point and the field capacity for each grid point. |
WMO GRIB2 definition
| Parameter |
|---|
| Discipline | 2 | land surface products |
| Parameter category | 0 | vegetation/biomass |
| Parameter number | 25 | volumetric soil moisture |
| 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 | n-1 for n-th soil layer |
| Type of second fixed surface | 151 | soil level** |
| Scale factor of second fixed surface | 0 | |
| Scaled value of second fixed surface | 1/2/3/4 | n for n-th soil layer |
**newly approved level type (WMO release in May 2016)
Level (all but Meteo-France) |
|---|
Type of first fixed surface | | soil layer |
Scale factor of first fixed surface | 0 | |
Scaled value of first fixed surface | soil layer number | |
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 |
Level (Meteo-France only) |
|---|
Type of first fixed surface | 106 | depth below land surface (m) |
Scale factor of first fixed surface | 0 | |
Scaled value of first fixed surface | 0 | |
Type of second fixed surface | 106 or 167***
| "depth below land surface (m)" or "bottom of root zone"***
|
Scale factor of second fixed surface | 1 or all bits to 1*** | (cm) or missing*** |
Scaled value of second fixed surface | value in cm or all bits to 1*** | 1 or missing*** |
*** valid for the 3rd Meteo-France layer (from surface to the bottom of root zone)
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