RRFS–MPAS: Add the U. Utah SLR field ("SDEN")

[jaymes-kenyon]

[Re-attempt of previous PR #1130, which was closed]

This PR addresses issue #1125.

Specifically, it adds the University of Utah snow-to-liquid ratio (SLR) diagnostic output to RRFS–MPAS applications, yielding a GRIB2 field abbreviated "SDEN". Recent development with this diagnostic occurred in the merged PR #1104; refer to that PR for more details.

Additionally, the current PR fixes an unrelated typo in code comments.

[WenMeng-NOAA]

@jaymes-kenyon @JesseMeng-NOAA My UPP standalone test for MPAS is at /home/Wen.Meng/stmp2/mpas_2024112100-after pn Hera. The new field "SDEN" was generated in WRFTWO dataset as:

wgrib2 WRFTWO12.tm00 -match SDEN -s -stats
40:36132094:d=2024112012:SDEN:surface:12 hour fcst::ndata=1905141:undef=1459740:mean=88.4948:min=45.653:max=679.477:cos_wt_mean=89.7173

Please let me know if you see issues in my test.

[WenMeng-NOAA]

@gspetro-NOAA You may start the UPP RTs on R&D machines. There should be no baseline changes with this PR.

[jaymes-kenyon]

@jaymes-kenyon @JesseMeng-NOAA My UPP standalone test for MPAS is at /home/Wen.Meng/stmp2/mpas_2024112100-after pn Hera. The new field "SDEN" was generated in WRFTWO dataset as:

wgrib2 WRFTWO12.tm00 -match SDEN -s -stats
40:36132094:d=2024112012:SDEN:surface:12 hour fcst::ndata=1905141:undef=1459740:mean=88.4948:min=45.653:max=679.477:cos_wt_mean=89.7173

Please let me know if you see issues in my test.

@WenMeng-NOAA — Thanks! Your test results look good to me. My own testing worked on Jet.

[WenMeng-NOAA]

The UPP RTs have been completed on WCOSS2 with no baseline changes. This PR is ready for merging.

[gspetro-NOAA]

RTs pass on Hera, Orion, and Hercules with no baseline changes.