question on regrid_data_plane

[haksulee]

Hello

I am new to MET and METPlus, and have a question on regrid_data_plane.
My goal is to regrid AORC data on the GEFSv12 grid.
Example files are AORC-OWP_2017103120z.nc4 and gep05.t00z.pgrb2.0p25.f060 at the google folder with an access permission to [email protected]: https://drive.google.com/drive/folders/1iVSAWBVb5Lsezf3A3dBZcFdDwx1Pt0EW

I downloaded docker images for met:11.1-latest and metplus:5.1-latest from https://dtcenter.org/community-code/metplus/metplus-5-1-existing-builds , and tried the following command inside a docker/container:

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root@d0431ca818f7:/met/met-11.1/tutorial/regridding# regrid_data_plane AORC-OWP_2017103120z.nc4 G130 output/a.nc -field 'name="APCP_surface"; level="surface";'
DEBUG 1: Start regrid_data_plane by root(0) at 2024-11-08 14:44:13Z cmd: regrid_data_plane AORC-OWP_2017103120z.nc4 G130 output/a.nc -field name="APCP_surface"; level="surface";
DEBUG 1: Reading data file: AORC-OWP_2017103120z.nc4
ERROR :
ERROR : process_data_file() -> "AORC-OWP_2017103120z.nc4" not a valid data file
ERROR :
root@d0431ca818f7:/met/met-11.1/tutorial/regridding#

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Based on https://mailman.ucar.edu/pipermail/met_help/2019-July/003574.html , I added file_type=NETCDF_NCCF;' -v2 which still didn't work

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root@d0431ca818f7:/met/met-11.1/tutorial/regridding# regrid_data_plane AORC-OWP_2017103120z.nc4 G130 output/a.nc -field 'name="APCP_surface"; level="surface"; file_type=NETCDF_NCCF;' -v2
DEBUG 1: Start regrid_data_plane by root(0) at 2024-11-08 14:29:51Z cmd: regrid_data_plane AORC-OWP_2017103120z.nc4 G130 output/a.nc -field name="APCP_surface"; level="surface"; file_type=NETCDF_NCCF; -v2
ERROR :
ERROR : CommandLine::next_option() -> unrecognized command-line switch "-v2"
ERROR :
root@d0431ca818f7:/met/met-11.1/tutorial/regridding#

---

Please, teach me how I can do regridding the AORC data correctly.

Thank you
Haksu

docker ps

d0431ca818f7 dtcenter/met:11.1-latest "/bin/bash" 23 hours ago Up 23 hours musing_margulis

docker image ls

dtcenter/met 11.1-latest 9b84d6d1cc66 4 months ago 3.78GB
dtcenter/metplus 5.1-latest 8ed1439300ae 15 months ago 3.93GB
dtcenter/metplus-training latest 52138718a387 15 months ago 2.24GB
dtcenter/metplus-data 3.1-met_tool_wrapper 1baf40d4fd28 4 years ago 1.13GB
dtcenter/met 8.1 aa0307df830c 4 years ago 2.68GB

[JohnHalleyGotway]

@haksulee, thanks for sending along your sample data. Good news, this data can be easily read by the MET tools. And yes, since the global conventions attribute is missing from the AORC-OWP_2017103120z.nc4 file to identify this as being a CF-compliant NetCDF file, you do need to use the file_type=NETCDF_NCCF; option to explicitly tell MET how to interpret it.

I do always recommend getting started with new datasets by running the Plot-Data-Plane tool. And doing so using verbosity level 4 (-v 4) will also print out timing information about the data being read. This step confirms that MET can read the data from your input file, place it at the right spot on earth, and the log messages confirm the metadata.

Here's a command to try:

plot_data_plane AORC-OWP_2017103120z.nc4 APCP_surface.ps \
name="APCP_surface"; level="(0,*,*)"; file_type=NETCDF_NCCF; -v 4

Here's some log output with the metadata:

DEBUG 4: Grid information:
DEBUG 4:    Projection: Lat/Lon
DEBUG 4:    Nx: 8401
DEBUG 4:    Ny: 4201
DEBUG 4:    lat_ll: 20.000
DEBUG 4:    lon_ll: 130.000
DEBUG 4:    delta_lat: 0.008
DEBUG 4:    delta_lon: 0.008
DEBUG 4:    wrapLon: false
DEBUG 4: 
DEBUG 4: Data plane information:
DEBUG 4:    plane min: 0
DEBUG 4:    plane max: 36.4
DEBUG 4:    valid time: 20171031_200000
DEBUG 4:    lead time: 000000
DEBUG 4:    init time: 20171031_200000
DEBUG 4:    accum time: 000000

And here's the resulting image:

And plotting 2m temperature with 'name="TMP_2maboveground"; level="(0,*,*)"; file_type=NETCDF_NCCF;' makes for a bit more colorful image:

Here's an example of running regrid_data_plane to regrid this data to NCEP Grid 130, using the default nearest neighbor interpolation method. See the User's Guide for more details on that:

regrid_data_plane AORC-OWP_2017103120z.nc4 G130 APCP_surface_G130.nc \
-field 'name="APCP_surface"; level="(0,*,*)"; file_type=NETCDF_NCCF;'

Here's a couple more details you may find useful.

• When setting the level string for NetCDF variables with 3+ dimensions, you need to define a string like this (N,*,*) where the *'s go into the slots for the spatial lat/lon dimensions. The N value is either a 0-based integer defining the index for that dimension (e.g. (0,*,*)) or a string defining it's value (e.g. (@20171031_200000,*,*)). All of the commands listed above would work with this level string too. For files with a time dimension of length 1, just putting 0 is easy enough. But for files with many time values, you may find specifying the timestring instead (in YYYYMMDD[_HH[MMSS]] format) to be more convenient.
• Yes, you can do regridding using the regrid_data_plane tool, but regridding on-the-fly is also supported by many of the MET tools. For example, if you ran Grid-Stat to compare data gep05.t00z.pgrb2.0p25.f060 forecast data to the AORC-OWP_2017103120z.nc4 analysis field, you could set up the configuration to regrid the forecast data to the observation domain with to_grid = OBS or vice-versa with to_grid = FCST. That way you can do it during the evaluation rather than having to run 2 commands... although both options work fine.

Hope this helps get you going. Glad it was an easy one!

[haksulee]

@JohnHalleyGotway

Hi John

Thank you very much for detailed explanation and help. I tried below which worked without errors:
regrid_data_plane AORC-OWP_2017103120z.nc4 G130 APCP_surface_G130.nc
-field 'name="APCP_surface"; level="(0,,)"; file_type=NETCDF_NCCF;'
I may try Grid-Stat later. The problem solved.

I have a different question.
Why separate docker images exist for met 11.1-latest and metplus 5.1-latest ?
In which case, should I use met 11.1 or metplus 5.1-latest ?
Can both met and metplus come in a single docker image ?

Thank you

[JohnHalleyGotway]

Yes, the METplus docker image is built on top of the MET docker image and adds the METplus Python wrappers.

For example, this command shows where plot_data_plane can be found inside that METplus container:

docker run -it --rm dtcenter/metplus:5.1-latest which plot_data_plane
/usr/local/bin/plot_data_plane

For the next coordinated release, METplus version 6.0.0, we're also adding the METplus Analysis Tools which provide additional Python plotting functionality. Prior to the introduction of METplus wrappers, some users ran the MET tools directly. But we definitely encourage running MET through the METplus Wrappers. So I'd recommend using dtcenter/metplus:5.1-latest.

[haksulee]

Ok, thank you very much for the explanation and the help. This discussion can be closed.