Strange T2 in WRF v4.4.2 and v4.5 after reinitialization

[Ying]

Hi all,

I am using WRF-Chem v4.4.2 under a triple nested domain (36 km, 6 km, and 1 km) in August 2019. In 6 km and 1km simulations, there is a strange T2 cold bias after several hours of reinitialization. Consequently, simulations crash. I tested different versions of WRF from v4.1.4 to v4.5 and found out that this issue happens in v4.4.x and v4.5.

I learned from your discussion on Strange T2 bias in newer WRF versions that the strange T2 bias can be attributed to the Noah-MP scheme. What I am using is the Unified Noah land-surface model. Could you give me any suggestions on the reason for it and how to solve this issue?

Best,
Ying

 

[haiqingsong]

Hi all,

I am using WRF-Chem v4.4.2 under a triple nested domain (36 km, 6 km, and 1 km) in August 2019. In 6 km and 1km simulations, there is a strange T2 cold bias after several hours of reinitialization. Consequently, simulations crash. I tested different versions of WRF from v4.1.4 to v4.5 and found out that this issue happens in v4.4.x and v4.5.

I learned from your discussion on Strange T2 bias in newer WRF versions that the strange T2 bias can be attributed to the Noah-MP scheme. What I am using is the Unified Noah land-surface model. Could you give me any suggestions on the reason for it and how to solve this issue?

Best,
Ying

Change the sf_surface_physics to other options such as 5.It will crash ？

 

[Ying]

Change the sf_surface_physics to other options such as 5.It will crash ？

Thanks for your suggestion!

It works well if I switch the sf_surface_physics to the thermal diffusion scheme (option 1). Option 5 can not work with urban canopy models. I am curious how to modify it to use the Noah land surface scheme.

 

[kwerner]

@Ying
I would recommend trying to get in touch with the group that develops/maintains the Noah/Noah-MP scheme to see if they have any suggestions. Based on that other thread you pointed to, they were working with someone on the issue, so it's possible they figured it out and just never came back to post a resolution. If you find one, please update here so other users will know in the future.