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Inconsistency between WRFV3 and WRFV4 (set issue?)

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I have been trying to do a baseline case between a set of runs using WRFV3.8 and WRFV4.2. When I was comparing my runs the WRFV4.2 runs were systematically 2-2.5 degrees cooler than the WRF3.8 runs. For these runs I am using the SCM for all my runs. Initially I was comparing runs using MYJ, MYNN2, and MYNN3. To further isolate this issue, I decided to run with the bl scheme turned off as well as the surface_physics scheme turned off. With those options off my results were very comparable. It appears that the differences are coming from the surface_physics scheme. When I run with the following options:
sf_sfclay_physics = 2,
sf_surface_physics = 2,
bl_pbl_physics = 0,
(no pbl scheme) the temperature issue arose again. Also I noticed the the Latent Heat Flux was significantly different (over 100Wm-2 difference…see attached). (see attached). I am trying to figure out if I have some sort of set-up issue that is causing this difference. I have attached my namelist files showing my settings. I am using the default input_sounding and input_soil that are default files in test/em_scm_xy.

The second strange behavior (and another thing making me leery about my 4.2 SCM build is that when I change my sf_surface_physics switch (e.g. = 1) the model runs even if I set the num_soil_layers switch inappropriately. I set num_soil_layers to 10 and wrf3.8 exited with a warning but the wrf4.2 ran as if nothing was wrong.

Please let me know if there is something I can check regarding my configuration that may be causing these large differences.


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Hi Glenn,
I'd first like to apologize for the delay in response to this. It seems this inquiry was overlooked. As it's been so long, have you moved past this, or would you still like assistance?