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# System prepended metadata

title: DE - IFS Runoff-mappingBrainst

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# DE - IFS Runoff-mapping
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## Brainstorming / What to do: 

**1. Remap drainage basin file from regular lat/lon to TCo. For now manually, later via raps. Tool: cdo**
- [x] Extract grib2 to make cdo readable: `grib_copy -w edition=2 input.grib output_grib2.grib`
- [x] `cdo griddes IMCGGhz9mINIT >tco79_griddes.txt`
- [x] `cdo remapbil,tco79_griddes.txt runoff_maps_regular.nc runoff_maps_tco79.nc`

**2. Build switch to turn runoff mapper on/off in IFS, and in FESOM. For now both to be controlled manually. Later raps can set both namelists from one switch**
- [x] find location in IFS code: Switch goes to `arpifs/setup/sumcc.F90`
- [x] implement switch
- [x] compile and check in NODES that switch works

**3. Build routine that reads in drainage basins.**
- [x] decide wether to use ICMGG????INIT grib file, or separate netcdf file
     -> Trying with NETCDF first
- [ ] Ask Nils Wedi / Sebastian Melinski
- [x] find location of where to read (`su0yomb` ~~or `su_surf_flds`?~~)
- [ ] code routine that reads the field
- [ ] compile and check that for a given lat/lon we get the right basins

**4. Write logic to collect the basin sum**
- [ ] Get area of local gridcell
- [ ] Get name of runoff flux
- [ ] Multiply area by runoff flux
- [ ] Add to 66 basin long local runoff vector
- [ ] do MPL_sum to get global runoff vector
- [ ] Hand over to FESOM2/NEMO
