Converting cubed sphere to lat/lon grid using JEDI

Converting cubed sphere to lat/lon grid using JEDI#

prerequisite#

jedi-bundle is already built in your JEDI_BUILD.

Usage and limitations#

fv3jedi_converttolatlon.x can be used to convert a cubed sphere file to a lat/lon grid. However, the user needs to specify which model level they want to perform the conversion on. This means that the executable doesn’t automatically regrid all the model levels.

An example of an input YAML file is below. You will need to specify:

  • Input geometry (under state geometry)

  • Details about the input file (under state)

  • Details about the latlon interpolation. More info here: ????

YAML structure:#

states to latlon:
- state geometry:
    fms initialization:
      namelist filename: geometry_input/fmsmpp.nml
      field table filename: geometry_input/field_table_gmao
    akbk: geometry_input/akbk72.nc4
    npx: 13
    npy: 13
    npz: 72
    field metadata override: geometry_input/geos_cf.yaml

  state:
    datetime: 2020-09-03T15:00:00Z
    filetype: cube sphere history
    state variables: [DELP,NO2,NO,O3,PS,SPHU]
    datapath: geos_c12/
    filename: geos_cf.bkg.20200903_150000z.nc4

  latlon interpolation:
    local interpolator type: oops unstructured grid interpolator
    resolution in degrees: 5.0  # low resolution for testing
    # need to use long names (see "field metadata override" file)
    variables to output: [air_pressure_thickness,volume_mixing_ratio_of_no2]
    pressure levels in hPa: [925, 850, 700, 500, 250]
    model levels: [71, 10]
    bottom model level: true
    datapath: output
    prefix: latlon.geos

Running convertstate#

First, set the path to your JEDI_BUILD and MPIEXEC. Running which mpiexec will return the path to your mpiexec. JEDI_BUILD is the path to your JEDI build directory.

Here is an example of setting these two variables:

export MPIEXEC=/discover/swdev/jcsda/spack-stack/openmpi-4.1.3/gcc-10.1.0/bin/mpiexec
export JEDI_BUILD=/discover/nobackup/mabdiosk/jedi-bundle/build-gnu-spack-1.5.1

All the files that you need are under convert_to_latlon directory. So cd convert_to_latlon and then you can run the application this command:

$MPIEXEC "-n" "6" $JEDI_BUILD/bin/fv3jedi_converttolatlon.x converttolatlon_geos.yaml 2>&1 | tee log_convert_to_latlon.txt

In this example, two files will be generated. The “PressureLevels” file will include the variables to output values in latlon grid for levels specified under pressure levels in hPa. Similarly, the “modelLevels” file will include the variables to output values in latlon grid for levels specified under model levels.

Another example of this application is ctest fv3jedi_test_tier1_converttolatlon_gfs in fv3-jedi. In this example, filetype of fms restart is converted from cubed sphere to latlon grid.

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