era5grib 2.0.1

Convert ERA5 data on NCI to WRF/UM input formatted GRIB data

era5grib

Convert NCI ERA5 archive data to GRIB format

Using era5grib

To use era5grib you will need to be a member of the hh5 (conda), rt52 (ERA5) and zz93 (ERA5-land) projects at NCI

Load the conda environment with

module use /g/data3/hh5/public/modules
module load conda/analysis3

Values over land

Variables over land use ERA5land instead of ERA5 surface values, as ERA5land is deemed to be more accurate. ERA5land values are regridded to the ERA5 grid using a bilinear interpolation method, with data over the ocean filled in using ERA5 surface values where available.

Currently ERA5 and ERA5-land have been extended backwards and now starts from 1950-01-01.

Using ERA5land can be disabled with the option --no-era5land

WRF output

era5grib can read in the model run dates from your WPS namelist, or you can specify the start and end dates on the command line. You can also pass in your geogrid output file and only that area will be converted to GRIB format.

era5grib wrf --namelist namelist.wps --geo geo_em.d01.nc --output GRIBFILE.AAA

The output can be passed to ungrib, using Vtable Vtable.ERA-interim.pl and metgrid using table METGRID.TBL.ERAI

UM output

The UM can only process one date at a time, which should be specified on the command line. The area to convert can be specified using any UM file on the target grid, e.g. the land mask.

era5grib um --time 20200101T1200 --target qrparm.mask --output era5.20200101T1200.grib

The output file should then be processed using the UM reconfiguration

Customising output

To modify the output of era5grib you can get it to output its data in netcdf format, modify that netcdf file, then convert to grib1 format with CDO

era5grib wrf --namelist namelist.wps --geo geo_em.d01.nc --format netcdf --output intermediate.nc

# Modify intermediate.nc as desired

cdo -f grb1 -t ecmwf copy intermediate.nc GRIBFILE.AAA