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(RESOLOVED) unable to do initial perturbation of T in the WRFV4.0

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jiaying

New member
Hello!
I have been performing some experiments with WRFV4.0 model by perturbing T in the wrfinput file, and I'm confirmed that I add the perturbation of T in the wrfinput file,but after modeling 24h, I find there isn't any different between the contrl expermient and the perturbation expermient. Therefore, I'm very confused about this, is there something special lead to this ?
Thanks!
 

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Hi,
I just want to verify that you have used a netcdf diffing tool/command to confirm that the results are bit-for-bit identical (and not that they just appear identical in output plots). If you haven't, can you use the diffwrf tool found in WRF/external/io_netcdf? It can be used with a command like:
Code:
./diffwrf wrfout_file_before_perturbed_T wrfout_file_after_perturbed_T
 
Thank you for your suggestion! I seem to find out how to resolve the question, but I don't know if it is right. In the WRFV4.0, the prognostic variable for temperature is moist potential temperature by default. In the wrfinput_d01, there are 3 variables about temperature: T(perturbation potential temperature theta-t0); T_INIT(initial potential temperature) and THM[either 1) pert moist pot temp=(1+Rv/Rd Qv)*(theta)-T0, or 2) pert dry pot temp=t], respectively.
Adding perturbation to T and T_INIT don't make any differences, I find to do initial perturbation of T in WRF4.0, I have to perturb the THM. When
I set use_theta_m=1, THM refers to moist potential temperature; when I set use_theta_m=0, THM refers to perturbation potential temperature, just T.
Is it right?
 
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