[Met_help] met and conditional verification across variables

[John Halley Gotway]

Mike,

You may be able to do what you'd like to do using what we've called "data
masking".  Listed below is an excerpt from the Point-Stat configuration
file describing the "mask_poly" option:

//
// Specify a comma-separated list of masking regions to be applied.
// An empty list indicates that no additional masks should be used.
// The masking regions may be defined in one of 4 ways:
//
// (1) An ASCII file containing a lat/lon polygon.
//     Latitude in degrees north and longitude in degrees east.
//     By default, the first and last polygon points are connected.
//     e.g. "MET_BASE/data/poly/EAST.poly" which consists of n points:
//          "poly_name lat1 lon1 lat2 lon2... latn lonn"
//
// (2) The NetCDF output of the gen_poly_mask tool.
//
// (3) A NetCDF data file, followed by the name of the NetCDF variable
//     to be used, and optionally, a threshold to be applied to the field.
//     e.g. "sample.nc var_name gt0.00"
//
// (4) A GRIB data file, followed by a description of the field
//     to be used, and optionally, a threshold to be applied to the field.
//     e.g. "sample.grb APCP/A3 gt0.00"
//
// Any NetCDF or GRIB file used must have the same grid dimensions as the
// data being verified.
//
// MET_BASE may be used in the path for the files above.
//
// e.g. mask_poly[] = [ "MET_BASE/data/poly/EAST.poly",
//                      "poly_mask.ncf",
//                      "sample.nc APCP",
//                      "sample.grb HGT/Z0 gt100.0" ];
//
mask_poly[] = [ "MET_BASE/data/poly/EAST.poly" ];

Option (4) listed above may do what you'd like.  You'd need the land use
field on the same grid as the data you're verifying.  Basically, you'd
specify the GRIB file you'd like to use, the field you want (land use in
your case), and then the threshold you'd like applied to that field - and
you could specify that threshold as "eq0" or "eq1" - or whatever the land
use values are.  That threshold defines the data mask that's applied to
the data.  You may specify as many of those masking regions as you'd like
- probably one per land use category you'd like to verify.

Hope that helps.

John Halley Gotway


> Hi.
>
>
>
> I'm interested in verifying conditionally; if(landuse==suchandsuch)then
> "how does surface temperature verify across cases and against
> observations/retrievals?" kind of thing.  Basically, doing what MET does
> with thresholds, but applying the threshold to other variables (preferably
> multiple - if(x<landuse<y)elseif(y<landuse<z) for instance) with a grib
> file, e.g..  Not finding that in MET: Am I missing something or is that
> something that's planned for a (near-)future release?
>
>
>
> Thanks,
>
> Mike
>
>
>
> ______________________________________________
>
> Michael Shaw, Contractor
>
> SAIC/NASA Support Scientist
>
> michael.shaw.ctr at offutt.af.mil
>
> 16WS Environmental Characterization
>
> HQ AFWA-SAIC
>
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>
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