strange ndown.exe result

[Alice_666]

Greetings,
I used the 1km wrfout results to drive a 200m simulation and completed it using ndown.exe. However, the results were very strange. I found that there were oscillations in the upper-air wind, which undoubtedly affected my simulation results. As a beginner of ndown, I'm not sure where the problem is.
Is it due to incorrect settings of some parameters? There were some errors during I use the wrfout files ,then I turned off the topo_wind.

Any thoughts are appreciated.

Thanks so much,

Interesting namelist.input variables:

 

[William.Hatheway]

I think it has something to do with the boundary conditions, can you share your namelist.input?

 

[Alice_666]

I think it has something to do with the boundary conditions, can you share your namelist.input?

ok,thank you very much ,This is my namelist.input

 

[William.Hatheway]

ok,thank you very much ,This is my namelist.input

what is your resolution of input for ndown?

 

[Alice_666]

what is your resolution of input for ndown?

Are you referring to the resolution I am using to drive ndown? Currently, I have wrfout results with a resolution of 1km, and I want to use ndown to obtain results with a resolution of 200m.

 

[Ming Chen]

Please turn on the option "diff_6th_opt", which can remove small wave structure of winds.
Let me know whether it helps.