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Interpolation problem with MPAS input files generated by WPS with real ERA5 grib data


New member
Dear All,
I've been having an issue running the ./init_atmosphere module when using real reanalysis (ERA5) data from Copernicus. I was able to run a simulation with real data from GFS, but I get an interpolation error with ERA5 data.
The error I get:
CRITICAL ERROR: Error in interpolation of st_fg to MPAS grid: num_st = 320

In another post, I read (CRITICAL ERROR: Error in interpolation of st_fg to MPAS grid) that this error is related to negative or zero temperature values in the data. I was able to confirm the information in the output log file:
Setting pressure field for isobaric data
Setting SST from SKINTEMP
Bad sm_fg -0.100000000000000E+31 1 2

I've found this post ((RESOLVED) Weird SST/SKINTEMP artifacts along coast) and looking in the METGRID.TBL.ARW from WPS I was able to detect the value:

The problem is that I use the FILES generated by ./ungrib.exe and even changing the value in the METGRID.TBL.ARW file, I keep getting the same error. I guess it is due to modifying a file used by ./metgrid.exe (since I use ungrib output and not the metgrid output), but I was not able to found where to modify a similar input to run a "correct" ./ungrib.exe.

I appreciate any help someone can give me or tell me if I'm doing some wrong procedure. I've attached the error files and namelist from MPAS. I use WPS 4.2 and MPAS 7.2.


  • log.init_atmosphere.0000.out.txt
    33.9 KB · Views: 9
  • namelist.init_atmosphere.txt
    1.1 KB · Views: 3