[Met_help] PWAT verification with MET Tools

John Halley Gotway johnhg at ucar.edu
Wed Nov 18 07:27:48 MST 2009


Just to be clear...
(1) Your forecast from WPP of precipitable water is a value that's integrated over the whole column of air above each grid point.
(2) Your point observations of precipitable water are the same - a value for the whole column of air above the observation point at the surface.

If that's true, I'd set up the PointStatConfig file as follows:
fcst_field[] = [ "PWAT/Z0" ];
message_type[] = [ "ADPSFC" ];

That means "give me the precipitable water field with a level value of 0", which is how's it's stored in your GRIB file.  And verify against "surface" observations.  When you call ASCII2NC, be sure to
encode these PWAT observations using the "ADPSFC" message type.

Give that a try and let me know if you have any problems.


Thomas Schwitalla wrote:
> John,
> I want to verify WRF forecasts (postprocessed with WPP)  with PWAT data
> from GPS stations. I already wrote it to NETCDF with ascii2nc but I
> haven't figured out how to edit PointStatConfig that I can use PWAT. My
> problem is: What value to set for the level type/code as PWAT is an
> integrated value?
> wgrib output looks as follows:
> PWAT kpds5=54 kpds6=200 kpds7=0 levels=(0,0) grid=255 atmos col 1hr fcst:
> Best regards,
> Thomas

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