Your geophysical fields should always match your model grid. They can be larger but should match every model grid point one-to-one.
Geophysical fields for GEM can get created with GenPhysX.
Geophysical fields are time invariant fields provided to GEM at the beginning of a simulation.
Dictionary of geophysical fields
| variable name | description | units / range |
|---|---|---|
| ME, MENF | topography elevation | m (may be negative, if below sea-level) |
| MG | land fraction (“land-sea mask”) | 0.0 – 1.0 (no unit) |
| VF | vegetation fraction per class (26 classes) | 0.0 – 1.0 (no unit) |
| VG | class number of dominant vegetation type of above classes | 1 – 26 (integer, no unit) |
| GA | glacier fraction ( same as VF(2) ) | 0.0 – 1.0 (no unit) |
| J1/J2 (ISBA) SAND/CLAY (CLASS) | percentage of sand/clay per layer J1/J2: 5 layers; SAND/CLAY : 1-n layers | 0.0 – 100.0 % |
| DPTH (CLASS) | depth to dedrock | m |
| LDPT (FLake) | lake depth | m |
| Z0 | (effective) total roughness length for momentum | m |
| ZP | ln(Z0) | no unit |
| ZTOP | orographic roughness length for momentum | m |
| ZVG2 | vegetation roughness length for momentum | m |
| SSS | subgrid orography SD (small scale) | m |
| LH | launching height | m |
| Y7,Y8,Y9 | subgrid topography gradient correlations | no unit |