How can we change the roughness of urban to that of farmland without changing land use?

[shuangchen]

I want to study the impact of cities on precipitation. I have replaced all urban landuse with farmland. I want to quantify the impact of urban heat island effect (UHI) and underlying surface roughness on precipitation. How should I design a sensitivity test? My idea is to only replace the roughness of urban landuse with the roughness of farmland. Is this ok? How can I achieve this?

 

[kwerner]

I believe this should be okay. You can do this by modifying the wrfinput file(s) with the new values and see if it works okay.

 

[shuangchen]

I believe this should be okay. You can do this by modifying the wrfinput file(s) with the new values and see if it works okay.

Thank you for your suggestion. I have tried, but found that the ZNT (TIME-VARYING ROUGHNESS LENGTH) in wrfinput is all 0. However, the ZNT in my wrfout is normal, and I don't know where the error occurred.

 

[kwerner]

I have tried, but found that the ZNT (TIME-VARYING ROUGHNESS LENGTH) in wrfinput is all 0. However, the ZNT in my wrfout is normal, and I don't know where the error occurred.

For clarification, are you modifying the wrfinput files, or the met_em* files? When you say that ZNT is normal in wrfout - does this mean the values are what you would expect?

 

[shuangchen]

非常感谢您的回复！我想尝试您的建议来修改 wrfinput 文件中的 ZNT，但我发现所有 ZNT 都是 0，因此我无法进行任何更改。