[Met_help] ASCII2NC

John Halley Gotway johnhg at rap.ucar.edu
Wed Jun 3 08:15:18 MDT 2009


Ann,

I'd like to respond to a few things here.

First, the current release of MET is version 2.0, released on April 7.
2009.  I'd suggest upgrading to the newer version if you get a chance. 
We've made several changes for METv2.0, some small, some big.

Second, whether you stick with METv1.1 or upgrade to METv2.0, please be
sure to grab the latest bugfixes for your releases.  Go to:

http://www.dtcenter.org/met/users/support/known_issues/METv1.1/index.php
... or ...
http://www.dtcenter.org/met/users/support/known_issues/METv2.0/index.php

Grab the tarball for the latest set of patches and follow the directions
for using them in your version.

To answer your first questions about how to delimit columns of data, any
whitespace character(s) should work.  You should be able to use one or
more spaces or one or more tabs.  So line up the data in whatever way you
find most convenient.

Regarding elevation data, and any other missing values in the ASCII
format, use -9999 to indicate missing.

Please take a look at slide 12 in the following presentation:
http://www.dtcenter.org/met/users/docs/presentations/MET_Tutorial_20090204/04_DataFormats.pdf

On there you'll note that MET does not actually use either the "elevation"
column of data or the "height" column of data from the ASCII format. 
We've included them in the format in anticipation of using that data in a
future release.  METv1.1 and METv2.0 both use a very simplistic method for
matching to points in the vertical that we inherited from the NCEP
verification tools.  The Point-Stat tool can verify forecasts at pressure
levels or at the surface.  And we do matching in the vertical for the
"surface" based only on the message type.  Message types of "ADPSFC" and
"SFCSHP" are considered to be at the surface.  So if you're verifying
2-meter temperature or 10-meter winds (which are "surface" variables), you
should verify against the "ADPSFC" or "SFCSHP" message type.  If you use
any other message type, Point-Stat shouldn't find any matched pairs.

In your use of MET, please let us know if that logic for matching in the
vertical is sufficient.  We're trying to gather feedback from users on
whether more sophisticated methods for matching in the vertical are
needed.

Thanks,
John Halley-Gotway
met_help at ucar.edu


> Hello,
>
> I'm using MET V1.1.  I'm trying to put our own observations into the ASCII
> Point Observation format.  I have a couple of questions.
>
> 1) Between columns, do we just use spaces or tabs?
>
> 2) If the elevation is missing, what do we put?  Is there a special number
> or code for missing data?
>
> Thanks for your help!
>
> Ann
>
> __________________________________
>
> Ann Mazuk
> Meteorological Satellite Systems
> The Aerospace Corporation
> El Segundo, CA  90245
> phone: (310) 336-3224
> fax: (310) 563-3035
> email: ann.mazuk at aero.org
> http://www.aero.org and http://www.aerospaceweather.com
>
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