[Met_help] Use of the ASCII2NC utility in MET

John Halley Gotway johnhg at rap.ucar.edu
Fri Nov 14 09:50:35 MST 2008

Hi Ed,

Barb, Randy, and I talked about your email yesterday regarding accumulating statistics for individual observation locations over time.  Currently, there's no "convenient" way to do this in one step,
but there is a less convenient way of doing it in many steps.  You could do the following:

- Define the list of station id's in which you're interested and place them in a file.
- In the Point-Stat config file, set the "mask_stations" parameter to that file containing the stations (each station in the list is considered a separate "masking region")
- Also, in the Point-Stat config file, set all of the "output_flag" values to 0, except for the last one for the matched pair lines.
- Run Point-Stat for each one of the forecast times in your period of interest to generate the matched pairs for your observation sites.
- Run the VSDB-Analysis tool to aggregate those matched pairs for each site and produce the types of stats you'd like to see.

So if you have N forecasts you'd like to evaluate, you'd run the ASCII2NC tool N times to reformat your observation points into N NetCDF files.  And you'd run Point-Stat N times to compare each
forecast to it's corresponding NetCDF observation file and dump out the matched pairs.  And then you'd run the VSDB-Analysis tool as many times as needed to compute whatever statistics you'd like to
compute from those matched pairs.

I'm happy to help if any questions come up, in particular, about running the VSDB-Analysis tool.

Regarding your question about the ASCII2NC tool, the answer is no, it won't cause a problem.  Just put in a value of "-9999" in the elevation column to indicate missing data.  In fact, Point-Stat
isn't currently using the elevation value at all!  We included it in there as a placeholder for the time being, anticipating that we may make use of it in the future.

And as Barb probably told you, were thinking about "slicker" ways of doing exactly what you're doing - accumulating verification results at individual locations in time.  It may or may not be included
in the METv2.0 release in February, 2009 depending on what we're able to get done by then.

Good luck.

Edward Tollerud wrote:
> I plan to use the ASCII2NC tool to do point verification of WRF
> forecasts, but I don't have elevations for my gage sites. Will this
> cause a problem in the reformatting and/or verification steps?
> Thanks for your help!
> Ed Tollerud
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