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Dependency of Coriolis force on stand_lon


New member

I have some confusion about the calculation of the momentum tendencies in WRF due to Coriolis forces.

The equations show a dependency on sin(alpha) and cos(alpha) where alpha, if I understand correctly, is the grid point longitude measured from the user defined stand_lon. If this is correct, does this mean the Coriolis force depends on how I chose stand_lon? and how can I choose it correctly for a Lambert projection as the results change accordingly?

Thanks a lot
The dependency on sin(alpha) and cos(alpha) is to address the grid-rotation issue. Note that WRF domain is rectangular, and the grid-relative U and V must be adjusted to lat-lon relative for the calculation of Coriolis force.
@Ming Chen Thanks for your answer. Can you elaborate more? How can I chose a value for stand_lon? I have tried multiple values for stand_lon and wind direction changes significantly.