Check for WRF THM variable USE_THETA_M setting

[braczka]

What's the issue?

In WRF-DART, a user can operate on the incorrect perturbed moist adiabatic potential temperature (instead of perturbed adiabatic potential temperature) if USE_THETA_M is not 0. This is well documented, but sometimes not readily checked if user is relying on older simulations of WRF.

Where did you find the issue?

WRF-DART OSSE using WRF 4.1.2

What needs to be fixed?

The DART code already makes THM in &model_nml mandatory, however doesn't check wrfinput_d01 attributes to confirm USE_THETA_M =0.

As a side effect the use of THM becomes mandatory when using perfect_model_obs, which technically shouldn't be a requirement.....

Suggestions for improvement

Perhaps error out if USE_THETA_M is not equal to zero in wrfinput. Do nothing is probably also a good option too. Placeholder until I get more feedback.

[hkershaw-brown]

Hi Brett, this pull request from October made THM mandatory, apparently due to the bounds check.
#728
edit: #733 is the pull request

[braczka]

Hi Brett, this pull request from October made THM mandatory, apparently due to the bounds check. #728 edit: #733 is the pull request

Yup -- I remember. What I didn't have the foresight to include in that PR was to also make the WRF THM attribute USE_THETA_M = 0 mandatory.