How to use ERA5 grib data to generate initial conditions files using chgres_cube?

[bnepal22]

I was attempting to get the initial condition tile files from ERA5 reanalysis data in grib format. I downloaded following pressure level and surface level data individually as a single grib file:

pressure_level_variables: 'divergence', 'fraction_of_cloud_cover', 'geopotential', 'ozone_mass_mixing_ratio', 'potential_vorticity', 'relative_humidity', 'specific_cloud_ice_water_content', 'specific_cloud_liquid_water_content', 'specific_humidity', 'specific_rain_water_content', 'specific_snow_water_content', 'temperature', 'u_component_of_wind', 'v_component_of_wind', 'vertical_velocity', 'vorticity'

surface or single level variables: '10m_u_component_of_wind', '10m_v_component_of_wind', '2m_dewpoint_temperature', '2m_temperature', 'land_sea_mask', 'mean_sea_level_pressure', 'sea_ice_cover', 'sea_surface_temperature', 'skin_temperature', 'snow_density', 'snow_depth', 'soil_temperature_level_1', 'soil_temperature_level_2', 'soil_temperature_level_3', 'soil_temperature_level_4', 'surface_pressure', 'volumetric_soil_water_layer_1', 'volumetric_soil_water_layer_2', 'volumetric_soil_water_layer_3', 'volumetric_soil_water_layer_4'

Then each downloaded data was converted to grib2 using eccodes and finally merged into single grib2 file to be used in chgres_cube script. However When I run the code I get the following errors:

#============= This error messsage appears just after reading grib2 data

/UFS/GFS.initial/20230530/ecmwf_20230530_t00z_sfc_plev_combined.grib2
**** ERROR: local table = 0 is not allowed, set to 1 ***
**** ERROR: local table = 0 is not allowed, set to 1 ***
**** ERROR: local table = 0 is not allowed, set to 1 ***
**** ERROR: local table = 0 is not allowed, set to 1 ***
**** ERROR: local table = 0 is not allowed, set to 1 ***
**** ERROR: local table = 0 is not allowed, set to 1 ***

#============= This message appears at last

• CALL FieldScatter FOR INPUT DZDT.
• READ TERRAIN.
• FATAL ERROR: READING TERRAIN HEIGHT RECORD.
• IOSTAT IS: 0
  application called MPI_Abort(MPI_COMM_WORLD, 999) - process 0

I have used the same GFSphys_var_map.txt without any modification.
It works perfectly for gfs data.

How to resolve this issue?

[GeorgeGayno-NOAA]

It is looking for terrain height and not finding it:
https://github.com/ufs-community/UFS_UTILS/blob/develop/sorc/chgres_cube.fd/atm_input_data.F90#L2794

[bnepal22]

It is looking for terrain height and not finding it: https://github.com/ufs-community/UFS_UTILS/blob/develop/sorc/chgres_cube.fd/atm_input_data.F90#L2794

Thank you for your quick response.
As per the atm_input_data.F90, the terrain height is pointing towards geopotential height at surface level ( if I am correct)
So I downloaded the geopotential at the surface from ERA5 data ( it is in m2/s2 so I converted it to m by dividing it by 9.8) and again combined it to the main grib2 file and rerun the chgres_cube. It again shows the same error: "FATAL ERROR: READING TERRAIN HEIGHT RECORD."

[GeorgeGayno-NOAA]

It is looking for terrain height and not finding it: https://github.com/ufs-community/UFS_UTILS/blob/develop/sorc/chgres_cube.fd/atm_input_data.F90#L2794

Thank you for your quick response. As per the atm_input_data.F90, the terrain height is pointing towards geopotential height at surface level ( if I am correct) So I downloaded the geopotential at the surface from ERA5 data ( it is in m2/s2 so I converted it to m by dividing it by 9.8) and again combined it to the main grib2 file and rerun the chgres_cube. It again shows the same error: "FATAL ERROR: READING TERRAIN HEIGHT RECORD."

Perhaps the ERA5 GRIB2 product definition for terrain (param category etc.) is not what chgres expects. See https://github.com/ufs-community/UFS_UTILS/blob/develop/sorc/chgres_cube.fd/atm_input_data.F90#L2802

[bnepal22]

It is looking for terrain height and not finding it: https://github.com/ufs-community/UFS_UTILS/blob/develop/sorc/chgres_cube.fd/atm_input_data.F90#L2794

Thank you for your quick response. As per the atm_input_data.F90, the terrain height is pointing towards geopotential height at surface level ( if I am correct) So I downloaded the geopotential at the surface from ERA5 data ( it is in m2/s2 so I converted it to m by dividing it by 9.8) and again combined it to the main grib2 file and rerun the chgres_cube. It again shows the same error: "FATAL ERROR: READING TERRAIN HEIGHT RECORD."

Perhaps the ERA5 GRIB2 product definition for terrain (param category etc.) is not what chgres expects. See https://github.com/ufs-community/UFS_UTILS/blob/develop/sorc/chgres_cube.fd/atm_input_data.F90#L2802

Finally, I found the solution to TERRAIN ERROR, which was mainly due to the parameter Number issue with the ECMWF grib2 file which was 4 and when I changed it to 5 then the error was resolved however another similar error about

• CALL FieldCreate FOR INPUT GRID T2M.
• FILE HAS 0 SOIL LEVELS
• FATAL ERROR: COUNTING SOIL LEVELS.
  which is yet again associated with the different grib parameters and I am attempting to copy it to gfs grib2 format.

I also tried by converting grib2 to netcdf and modifying chgres_cube.sh script.
changed grib2 to gaussian_netcdf in :

INPUT_TYPE=${INPUT_TYPE:-"gaussian_netcdf"}

and
ATM_FILES_INPUT=/UFS/GFS.initial/20230530/ecmwf_20230530_t00z_sfc_plev_combined.nc
ATM_CORE_FILES_INPUT=${ATM_CORE_FILES_INPUT:-NULL}
ATM_TRACER_FILES_INPUT=${ATM_TRACER_FILES_INPUT:-NULL}
SFC_FILES_INPUT=${sfc_path}'/facsf.1.0.nc,'${sfc_path}'/facsf.1.0.nc,'${sfc_path}'/maximum_snow_albedo.0.05.nc,slope_type.1.0.nc,'${sfc_path}'/snowfree_albedo.4comp.0.05.nc,'${sfc_path}'/soil_type.statsgo.0.03.nc,'${sfc_path}'/substrate_temperature.1.0.nc,'${sfc_path}'/vegetation_greenness.0.144.nc,'${sfc_path}'/vegetation_type.modis.igbp.0.03.nc'
NST_FILES_INPUT=${NST_FILES_INPUT:-NULL}
GRIB2_FILE_INPUT=${GRIB2_FILE_INPUT:-NULL}
#GRIB2_FILE_INPUT=$4
TRACERS_INPUT=${TRACERS_INPUT:-'"spfh","clwmr","o3mr","icmr","rwmr","snmr","grle"'}
GEOGRID_FILE_INPUT=${GEOGRID_FILE_INPUT:-NULL}
But it throws OPEN ERROR.
Are there any other paramter I have to modify to use netcdf data?