[Met_help] ascii2nc and point_stat: an update

[John Halley Gotway]

Jonathan,

Good catch.  I'm glad you found that.

Please copy two attached files into the directory
METv2.0beta8/lib/vx_util, rebuild, and then try rerunning your data
through ASCII2NC and Point-Stat.

Please let me know if that does the trick for you.

In ASCII2NC we are supposed to be keeping track of the header data and
only incrementing the header id when the header data actually changes. 
However, the lines that are doing the comparison to see if the message
type, station id, and valid time have changed were not working properly. 
Hopefully this will fix it.

The reason we require that the U and V component of winds be grouped
together is to make things a bit simpler.  Since we have to deal with them
as pairs in a couple of places in the code:
- in Point-Stat in the computation of VL1L2 vector partial sums
- in PB2NC in deriving wind speed
It's easier to just require that one follows the other.  Otherwise, we'd
waste a lot of time hunting through thousands the observations looking for
U's and V's to match up.  I'm glad you were able to reorder you data to
accomodate that.

Thanks,
John

> John,
>
>
>
> Well, I tried sorting my daily output file by valid time.  As a result,
> I have each individual observation with all the variables grouped
> together on consecutive lines in the input file to ascii2nc.  However,
> the netcdf output from ascii2nc still did not group the common wind
> observations into the same hdr_id.  Could this be a problem with the
> ascii2nc program in v2Beta?    It seems like the wind component data
> need to be written to the same hdr_id in the obs_arr().
>
>
>
> For example, here's what I see in the PB2NC ncdump output:
>
>
>
> obs_arr =
>
>   0, 33, 1011.4, -9999, -5.1,
>
>   0, 34, 1011.4, -9999, 0,
>
>   0, 32, 1011.4, -9999, 5.1,
>
>   1, 11, 1011.4, 4.00206, 302.05,
>
>   1, 7, 1011.4, 4.00206, 4,
>
>   1, 17, 1011.4, 4.00206, 297.8651,
>
>   1, 2, 1011.4, 4.00206, 101186.8,
>
>   2, 33, 1012.1, -9999, -4,
>
>   2, 34, 1012.1, -9999, 0.7,
>
>   2, 32, 1012.1, -9999, 4.060788,
>
> .
>
> .
>
> .
>
>
>
> Notice that any wind information is grouped together under the same
> hdr_id (first column) whereas the other remaining scalar variables
> (T/Z/Td/PMSL) are grouped under their own common hdr_id.
>
>
>
> Meanwhile, the output from ascii2nc shows up as follows in an ncdump:
>
>
>
> obs_arr =
>
>   0, 11, -9999, 4, 301.15,
>
>   1, 17, -9999, 4, 296.15,
>
>   2, 2, -9999, 4, 101660,
>
>   3, 31, -9999, 4, 77.69,
>
>   4, 32, -9999, 4, 4.63,
>
>   5, 33, -9999, 4, -4.52,
>
>   6, 34, -9999, 4, -0.99,
>
>   7, 11, -9999, 319, 302.15,
>
>   8, 17, -9999, 319, 290.15,
>
>   9, 31, -9999, 319, 269.8,
>
>   10, 32, -9999, 319, 3.6,
>
>   11, 33, -9999, 319, 3.6,
>
>   12, 34, -9999, 319, 0.01,
>
> .
>
> .
>
> .
>
>
>
> Notice how each new line of data corresponding to a new variable has a
> new hdr_id, instead of grouping them together as in the PB2NC output.
>
> This seems to correlate well with the point_stat error message I receive
> when trying to process the UGRD/VGRD/WIND variables:
>
>
>
> ERROR: process_obs_file() -> when computing vector winds, each UGRD
> observation must be followed by a VGRD observation with the same header
> and at the same level
>
>
>
> I thought this additional feedback might be helpful towards your
> diagnosis.
>
> Regards,
>
> Jonathan
>
>
>
>
>
> ***********************************************************
> Jonathan Case, ENSCO, Inc.
> Aerospace Sciences & Engineering Division
> Short-term Prediction Research and Transition Center
> 320 Sparkman Drive, Room 3062
> Huntsville, AL 35805-1912
> Voice: (256) 961-7504   Fax: (256) 961-7788
> Emails: Jonathan.Case-1 at nasa.gov
>
>              case.jonathan at ensco.com
>
> ***********************************************************
>
>
>
>
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