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Surface layer scheme

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New member
I have a question about the surface layer scheme selection used in WRF 3.4.1.

We had run three simulations with YSU, MYJ, and MYNN boundary layer physics. The WRF Users' Guide for version 3.4 says to use one surface layer scheme for YSU and another for MYJ. MYNN could use either of these surface layer schemes, or an alternate third surface layer scheme. The model sometimes forces users to use certain combinations consistent with these restrictions.

Is this surface layer forcing present in WRF version 3.4.1?

What surface layer schemes are forced at run time for each of the boundary layer schemes YSU, MYJ, and MYNN? Is it possible that all three of these schemes can run on the same surface layer scheme without WRF automatically forcing a certain scheme? We do not have the namelist files anymore but we do have the wrfout files, is there any way to identify which surface layer scheme was used based on the wrfout file?

The reason for the model forcing users to use a certain combination of schemes is because they are compatible with each other, while some others are not compatible. If the Users' Guide for V3.4.1 says that you must use those combinations, then you probably will have to. It's possible the model would run with others, but may not give reasonable results. You can test whether the model actually forces the use by doing some quick/simple simulations.

To determine the schemes used, you can issue the following:
ncdump -h wrfout_d01_date_time
(obviously you would use the actually date and time string of your file)
and then look somewhat near the bottom of the print-out for sf_sfclay_physics. You should see something like:
This should tell you the number of the scheme chosen.