HR4 Gravity Wave Drag Update

[Qingfu-Liu]

Description

(Instructions: this, and all subsequent sections of text should be removed and filled in as appropriate.) Provide a detailed description of what this PR does.

1. This update is a combination of the gravity wave drag (GWD) versions from the NOAA/GSL and NOAA/PSL

2. The test results with this update can be seen in: a) summer: https://www.emc.ncep.noaa.gov/gmb/jhan/vsdbw/hr3e50s b) winter: https://www.emc.ncep.noaa.gov/gmb/jhan/vsdbw/hr3d11w HR4GWD: same as HR3 but with the updated GWD

   Compared to the HR2 and HR3, the HR4GWD shows a significant improvement especially in 500mb height AC and CONUS precipitation forecast skills. The HR4GWD reduces the cold and dry biases in the lower troposphere compared to the HR3. It also reduces the negative wind speed biases in the troposphere compared to the HR2.

Is a change of answers expected from this PR?
Yes. Change of answers is expected

Issue(s) addressed

Gravity Wave Drag Update for HR4

Testing

How were these changes tested?
yes. see previous description

Are the changes covered by regression tests? (If not, why? Do new tests need to be added?) No. Need to create new input.nml and new fix file ugwd Have the ufs-weather-model regression test been run? On what platform?
Regression test has not been run.

• Will the code updates change regression test baseline? If yes, why? Please show the baseline directory below.
• Please commit the regression test log files in your ufs-weather-model branch

Dependencies

If testing this branch requires non-default branches in other repositories, list them. Those branches should have matching names (ideally) Tests need new input.nml file and new fix file ugwd Do PRs in upstream repositories need to be merged first? None