Refine the vector level matching logic when reading NetCDF output generated by other MET tools

[JohnHalleyGotway]

Describe the Enhancement

This issue arose via the dtcenter/METplus#2898 discussion. The task is to enhance the vx_data2d_nc_met library to better support computing VL1L2/VAL1L2/VCNT vector statistics at multiple levels when reading data from MET NetCDF files.

Demonstrate the issue to be addressed by running the following commands:

cp $MET_TEST_INPUT/model_data/grib2/gfs/gfs.0p25.2022092400.f012.grib2 .

# Run Regrid-Data-Plane to create a MET NetCDF file with U/V records at multiple pressure levels
regrid_data_plane \
gfs.0p25.2022092400.f012.grib2 \
gfs.0p25.2022092400.f012.grib2 \
regrid_UV.nc \
-field 'name="UGRD"; level="P250";' \
-field 'name="VGRD"; level="P250";' \
-field 'name="UGRD"; level="P500";' \
-field 'name="VGRD"; level="P500";'

# Run Grid-Stat to compute VL1L2 at multiple pressure levels
grid_stat regrid_UV.nc regrid_UV.nc GridStatConfig_UV -v 3

Where GridStatConfig_UV includes:

fcst = {
   field = [
      { name = "UGRD_P250"; level = "P250"; is_u_wind = true; },
      { name = "VGRD_P250"; level = "P250"; is_v_wind = true; },
      { name = "UGRD_P500"; level = "P500"; is_u_wind = true; },
      { name = "VGRD_P500"; level = "P500"; is_v_wind = true; }
   ];
}
obs = fcst;

And generates the following warning messages:

DEBUG 3: U-wind field array entry 1 matches V-wind field array entry 2.
DEBUG 3: U-wind field array entry 1 matches V-wind field array entry 4.
WARNING: 
WARNING: GridStatConfInfo::process_config() -> For U-wind, found multiple matching V-wind field array entries! Using the first match found. Set the "level" strings to differentiate between them.
WARNING: 
DEBUG 3: V-wind field array entry 2 matches U-wind field array entry 1.
DEBUG 3: V-wind field array entry 2 matches U-wind field array entry 3.
WARNING: 
WARNING: GridStatConfInfo::process_config() -> For V-wind, found multiple matching U-wind field array entries! Using the first match found. Set the "level" strings to differentiate between them.
WARNING: 
DEBUG 3: U-wind field array entry 3 matches V-wind field array entry 2.
DEBUG 3: U-wind field array entry 3 matches V-wind field array entry 4.

• Fix the logic to actually use the specified level string when determining the U/V matches.

In addition:

• Be sure to add a new unit test to demonstrate this usage in grid_stat or point_stat.
• Unrelated, but also remove line 68 of temp_file.cc (int errno;) since it is NOT needed and may cause a compilation error as described in the Error when installing METplus--12.0.2 METplus#2897 discussion.

Time Estimate

< 1 day

Sub-Issues

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None needed.

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Funding Source

Spend up to 2 h of NCAR base (2702701)

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