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Standard Deviation of Wind Speed and Vertical Velocity?

Josh

New member
I have been perusing the WRF Registry and have found that it appears WRF is able to output the standard deviation of the wind speed at a 10 meter height in m/s.

Does anyone know if WRF is able to output the standard deviation of the wind speed or standard deviation of the vertical velocity at eta levels?

If not, is it feasible for a user to implement the ability for WRF to output these diagnostic variables, or would it be a "hefty undertaking"?

Josh
 
Hi Josh,
Apologies for the delay in response and thank you for your patience.
I assume you're referring to the "climate diagnostics" (or output_diagnostics = 1) option? If so, using this method to do the same for vertical velocity is not already included in the code, but it may be something you can do. You could look at the existing code (in phys/module_diag_cl.F) and use one of the other variables as a template to add the same for vertical velocity. I've not played around with this code, so I can't say how difficult it would be, but you could take a look and see what you think. If you do modify the code, you'll need to recompile WRF to use the changes. You don't need to clean or reconfigure the code, though. Just simply recompile.

You may also want to look through this section of the WRF Users' Guide to see all of the output diagnostics options available.
 
Hi kwerner,
Thanks for your reply. I looked at the code in this file, but I think what I want is the standard deviation at each eta level for the horizontal wind speed, and w velocity. It appears the above climate diagnostics uses 2d arrays only (ij) since it is at a specific level?

My goal is to output a value for the standard deviation of the horizontal wind speed, and standard deviation of the w velocity for each grid cell at all levels. (So instead of getting ('u', 'v', 'w',...) WRF output at each model level, I would get ('u', 'v', 'w', 'standard deviation of horizontal wind speed', 'standard deviation of w velocity',...).

My understanding is that the standard deviation would be based on all the individual time step values within each WRF history interval. Would/should I edit a different Fortran file to do this? Thanks.
 
Hmm, yeah I'm not sure there is an option to do something like that; however, I believe you could use the format of another 3d variable to add this in. Take a look at this presentation. It's got a lot of useful information, but if you skip ahead to the "Adding an Array" section, that may be helpful to you. Perhaps this example could also be helpful.
 
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