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wrong results for vertical interpolation

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.

mihaela

New member
Dear colleagues,
I would be very grateful to you if you could suggest me a solution to the following problem:
I am getting wrong results when I interpolate the "Input levels" to the "Output levels" below using v_interp.f with the namelist namelist.v_interp

Input levels:
0.9965, 0.988, 0.9765, 0.962, 0.944, 0.9215, 0.8945, 0.8603331, 0.8209995,
0.7816658, 0.7423322, 0.6876204, 0.6201558, 0.5577776, 0.5001666,
0.4470201, 0.3980519, 0.352991, 0.3115812, 0.2735803, 0.2387594,
0.2069025, 0.1778055, 0.1512759, 0.1271324, 0.1054426, 0.08629248,
0.06946232, 0.05467107, 0.04167173, 0.03024721, 0.02020674, 0.01138263,
0.00362753 ;
Output levels
eta_levels = 1.000, 0.999, 0.998, 0.997, 0.995,
0.992, 0.989, 0.985, 0.980, 0.974,
0.967, 0.959, 0.950, 0.940, 0.928,
0.914, 0.898, 0.880, 0.860, 0.838,
0.814, 0.788, 0.760, 0.730, 0.695,
0.655, 0.610, 0.565, 0.515, 0.465,
0.415, 0.360, 0.305, 0.245, 0.188,
0.132, 0.080, 0.035, 0.000

Many thanks in advance.
Best regards,
Mihaela
 
This topic has been moved to the WRF Utilities section of the forum, as the v_interp program is a utility. Someone will follow up with this post soon.
 
When adding vertical levels, please keep the first- and the last-half levels the same as in the input file itself. If levels are added outside the range, the result might be wrong. Please double check your settings.
 
Thank you very much for the answer.
Still I would like to understand why the rule does not apply always.
When I use the following output levels it works:
1, 0.997, 0.993, 0.987, 0.979, 0.97, 0.959, 0.946, 0.931, 0.915, 0.896,
0.875, 0.853, 0.828, 0.802, 0.774, 0.743, 0.711, 0.677, 0.641, 0.604,
0.565, 0.525, 0.484, 0.444, 0.403, 0.363, 0.323, 0.285, 0.249, 0.214,
0.181, 0.151, 0.124, 0.099, 0.076, 0.056, 0.039, 0.024, 0.011, 0 ;
 
This utility has no extrapolation function. It behaves to increase the vertical resolution within the original vertical range. To better understand this utility, please read relevant codes and publications.
 
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