New bc nudging on r3l

[gbolzon]

closes #5

[gbolzon]

At the moment IC/create_2basins_restarts.py creates

• the IC
• the BC nudging file with identical content

BC/bclib/r3l.py -m $MASKFILE -o R3l.nc generates resto file

[ggalli00]

create_N-basins_restarts.sh launches create_R3l_nudging.py and create_N-basins_restarts.py.

These scripts use satellite RRS412 fields and tuned R3l values in nwm and lev3 to generate reconstructed R3l surface fields by sub basin. Then it applies some smoothing and extends at depth with a sigmoid.

NB, scripts are very dirty and point at g100 directories that may no longer exist. use with caution.