[Met_help] Observed winds for point-stat

[John Halley Gotway]

Steve,

Since point observations are usually defined to be earth-relative rather than grid-relative, we set up MET to handle the rotation of winds from grid-to-earth relative.

When verifying U, V, or wind speed, MET reads in the components from a GRIB file and checks the GRIB file to see if the winds are defined to be grid-relative.  If they are, it rotates them to be earth
relative before comparing to the point observations in Point-Stat.

Therefore, the earth-relative point observation values should be used.

But there are those bugs in the rotation of winds that you uncovered in the METv1.1 code.  So make sure that you've updated your source code with the latest bug fixes prior to verifying winds.
http://www.dtcenter.org/met/users/support/known_issues/METv1.1/index.php

Thanks,
John

Masters.Steve wrote:
> I'm pretty sure I know the answer, but I want to be sure...
> 
> When producing observed wind data files for point-stat (via assci2nc),
> do we need to rotate the wind directions into the WRF grid, or do we use
> the reported earth-relative wind directions from the observations?
> 
> Some of the nudging/initialization documentation with WRF seem to
> indicate that is necessary for creating observed data files for the WRF
> simulations.  I haven't seen any mention of it for MET, but I want to
> make sure.
> 
> Steve Masters   masters.steve at ensco.com
> ENSCO, Inc.
> Melbourne, FL
> 
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