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Unknown reason for difference between idealized runs in x- and y- directions

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littleLi

New member
To whom it may concern,

I am trying to implement a new surface drag method in WRF, so I want to check the symmetry in x- and y- directions.

The point I started at is the default WRF (no new code implemented), 2d idealized bell shaped mountain case (WRF/test/em_hill2d_x). I changed the default namelist.input to higher resolution, and changed the related part of code in dyn_em/module_initialize_ideal.F, namelist.input, and input_sounding to get a symmetric run in y-direction. Surprisingly, the two results are not the same.

Then I tried to test the asymmetry I saw above, I changed the run from 2d to 3d. The mountain is still bell shaped, and totally symmetric in x- and y- directions. The only difference between my two runs are the input_sounding files, the winds are kept at 10m/s and potential temperatures are kept at 273K at all levels, the only difference is the wind is from west/south. Picture attached is drawn by ncview and you can see the obvious asymmetry between the two runs (U field in the left pic and V field in the right one, same color bar).

I am not sure what to do now, do you have any idea why there's the asymmetry between two directions?

Besides the picture, namelist.input is attached here. 3D test runs last for 5 minutes, resolutions are 40m, and runs are set to be open boundaries.

Thanks,

Li
 

Attachments

  • 800m_symmetric.png
    800m_symmetric.png
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  • namelist.input
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I am a little confused about this email. Please clarify:

"The point I started at is the default WRF (no new code implemented), 2d idealized bell shaped mountain case (WRF/test/em_hill2d_x). I changed the default namelist.input to higher resolution, and changed the related part of code in dyn_em/module_initialize_ideal.F, namelist.input, and input_sounding to get a symmetric run in y-direction. Surprisingly, the two results are not the same."


By saying the "two results are not the same", you mean which two? Also,
(1) based on which version of WRF did you modify the code?
(2) how did you modify the code? Please send me a copy of your code

Please clarify what you want to do and what results you expect. Is there any reference for this work?
 
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