## 1. Description

For each geographical zone (North-West (NW) of France and South-East (SE) of France), two different masks are stored in a GRIB file:

• the land-sea mask, stored in the lsm file. The values are binary : 0 for sea and 1 for land.

• the relief mask, stored in the p3008 file. The values are in meters.

The spatial resolution of the masks is 0.025°.

Note : When you open a GRIB file with the library xarray, a new associated .idx file is created.

## 2. Files organization

The files are stored by zone :