Describe the Problem

This was brought to our attention in Discussions #2033. When the user places the convert function of K_to_C(x) as follows, MET produces climatology field output that is 2x the requested amount:

////////////////////////////////////////////////////////////////////////////////

//
// Climatology data
//
climo_mean = {
   convert(x) = K_to_C(x);
   file_name = ["pgba_mean.19590115"];
   field     = [{name ="TMP"; level="Z2";}];
   regrid = {
      method     = NEAREST;
      width      = 1;
      vld_thresh = 0.5;
      shape      = SQUARE;
   }

This behavior was confirmed in both MET-11.0.0 and the nightly build. It was also consistent regardless of the requested conversion (e.g. 2*x,log10(x)).

The short-term fix was identified by @JohnHalleyGotway, which places the convert function inside the field array. This produces the expected output:

////////////////////////////////////////////////////////////////////////////////

//
// Climatology data
//
climo_mean = {
   file_name = ["pgba_mean.19590115"];
   field     = [{name ="TMP"; level="Z2"; convert(x) = K_to_C(x);}];
   regrid = {
      method     = NEAREST;
      width      = 1;
      vld_thresh = 0.5;
      shape      = SQUARE;
   }

Additional issues were discovered during this issue investigation.

The first is that in the GridStatConfig_Default, https://github.com/dtcenter/MET/blob/main_v11.0/data/config/GridStatConfig_default, the match_month setting in the climatology mean dictionary is still present. This setting has been deprecated and should be removed.

The second is that in a Point-Stat unit test,

The third is that when providing a single monthly climo file with 4 times, 00, 06, 12, and 18, and requesting an off-hour (i.e. 03), no matching climo data is found. Instead, MET should use the 00 and 06 hours and apply the specified interpolation logic.

Here's a summary of things to fix:

• Limit the scope of data censoring and conversion defined in the regrid dictionary.
• Remove deprecated match_month setting from GridStatConfig files.
• Fix climo timing issue for off-hours when only 1 monthly climo file is provided.
• Add Point-Stat unit test that demonstrates unit conversion operations to main_v11.0 and enhance it.
• Add Grid-Stat unit test to demonstrate climo timing logic when processing a single monthly input with off hours.

Expected Behavior

For the main bug issue (climo), the convert function should produce the same results regardless of if it's placed in the field array or outside it.

For deprecated variable, it simply shouldn't be there.

And for the unit test, the unit columns for the forecast and observation data should be populated via set_attr_units

Environment

Describe your runtime environment:

1. Machine: Seneca
2. OS: Linux
3. MET 11.0.0 and NB20230202

To Reproduce

Describe the steps to reproduce the behavior:

1. Use climo data of your choice in Grid-Stat (or any tool), populating the dictionary as described above. Make sure to request netCDF output for climo for quickest visual confirmation
2. run Grid-Stat as usual
3. Open output netCDF file and view climo field.

Relevant Deadlines

Bugfix for MET 11.0.1

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