I would like to know what is the recommended grid size (if any) when using the topo_wind option.
This is an excerpt from UEMS run_physics.conf:
However I'm not able to find any other (WRF official) documentation that says that the topo_wind would work as expected only for high resolution simulations.Topographic correction for surface winds to represent extra drag from sub-grid topography and enhanced flow at hill tops. Shown to reduce 10m wind biases, which is good, but designed for dx < 2km, which is a bummer.
I also see a lot of other users use it for any grid size (from dx=36000 to dx=500).
I have run my own experiments (with dx=6000) and my conclusion is that although it does a good job in correcting the wind speed, the latter seems to be underestimated in the plains (with a factor of 1.2-2).
I would highly appreciate your experience and opinion guys! Thanks much in advance.
P.S. This is regarding UEMS V15.89 (WRF 3.7.1) in 1-way nesting configuration (dx=6000, 2000).