Any advice for boundary condition of small domain

[JSY]

Hi all,

I'm working on my research about conducting ideal simulation with real terrain.
However, I found an issue with the boundary condition. There is unrealistic convection at the boundary.
I used symmetric because periodic didn't make sense.

This is the land use index of my domain and if I set the boundary condition as periodic, the model thinks there is ocean in the north and east boundary side and there is land in west and south side.

However, it is not true. The blue and purple part (land) is a part of my country so there should be land in the onrth and east side.

So I chose symmetric and after running wrf I got the result below.

This is hourly rainfall and you can see there is rainfall on an upper-left side.

I also tried modifying share/module_bc.F like below.

IF( variable == 'u' ) THEN

DO j = MAX(jds,jts-1), MIN(jte+1,jde+jstag)
DO i = 0, bdyzone-1
!dat(ids-i,j) = - dat(ids+i,j) ! here, u(0) = - u(2), etc
dat(ids-i,j) = dat(ids,j)
ENDDO ! normal b.c symmetry at u(1)
ENDDO

I applied this in the all side of the boundary in the code.
This means the u or v wind will maintain their direction at the boundary, unlike the original symmetric condtion.

However it didn't work, and the result was quite the same.

If you have any ideas to reduce the convergence at the boundary, please let me know.

 

[kwerner]

Hi,
I'd like to apologize for the very long delay in response while we've had to tend to other obligations. Thank you for your patience. Since it's been so long, I first want to ask if you're still experiencing this issue.

 

[JSY]

Yes I'm still struggling with this issue. I just zoomed the area of interest and anaylizing it. But I still unsure how to handle the boundaries.

 

[kwerner]

Apologies again for the delay. Can you let me know which ideal case you're using, and what method you are following to add real terrain to the domain? If you modified any of the code files, can you attach those, so I can compare to the original versions? Thanks!