vertical velocity WW

[rameshv]

Dear WRFhelp,

I am looking for the vertical velocities generated by real package from the ERA-interim inputs
used in METGRID.

The METGRID.TBL doesn't seem to include the WW input. What should I do to include the
WW input so that the wrfinput* files include the vertical z-wind (WW).

I remember MM5 interpf package used to generate vertical z-winds.

Just drop a line about the above.

Thanks,
Best,
Ramesh

 

[kwerner]

Hi,
Vertical velocity is calculated by the WRF model, itself, and therefore isn't found until after running wrf.exe. The only time it is output by the real program is when cycling is done (e.g., for WRFDA), but for a basic WRF run, it's not necessary at that stage. The WPS program uses input data (e.g., ERA-interim) to horizontally interpolate variables onto the domain, and then real.exe does vertical interpolation for the 3D meteorological fields and the sub-surface soil data to create initial and boundary conditions. WRF then uses those variables, combined with physics schemes, etc. to create forecasts over a time period, and that is when W is output.
At one time the real program had an option to interpolate W based on the horizontal wind fields and terrain height, but it was determined that the model wasn't sensitive enough for this and created unrealistic values, so it was removed.