John,<br>Make sence. I will continue to test it. Thank you so much for detailed explaination.<br><br>Ruifang<br><br><div class="gmail_quote">On Fri, Aug 21, 2009 at 8:06 AM, John Halley Gotway <span dir="ltr"><<a href="mailto:johnhg@rap.ucar.edu">johnhg@rap.ucar.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Ruifang,<br>
<br>
The behavior you're seeing is correct. The MPR output would be the same. However, the values in the contingency tables (CTC line type, for example) should be different when choosing different<br>
thresholds.<br>
<br>
Here's what's going on... When you run Point-Stat, you can think of it as setting up a bucket for each combination of forecast field/masking region/interpolation method. So for example, suppose you<br>
configure Point-Stat to verify 2-meter temperature and 500mb temperature over 3 masking regions, your FULL domain and then two subdomains. And you're using the nearest neighbor interpolation method.<br>
In this case, we'd be verifying 2 fields over 3 regions using 1 interpolation method. So Point-Stat will set up 6 "buckets", 3 for 2-meter temp and 3 for 500mb temp.<br>
<br>
Next, Point-Stat looks at each one of the point observation values you've passed to it. If the observation type (i.e. 2-m temp) matches the forecast type, and it's in the correct masking region,<br>
it'll interpolate the forecast values to the observation location to create a matched pair. Then it throws that matched fcst-obs pair into the appropriate bucket. Point-Stat processes through all of<br>
the point observations in this way, computing matched pairs, and throwing them in the right buckets.<br>
<br>
After that's finished, it'll compute whatever statistics you've requested using whatever threshold values you've set. For example, if you set threshold values of ">273.0" and ">283.0" for 2-m temp,<br>
it'll apply those to all of the matched pairs in the "bucket" and compute contingency tables and stats. However, the choice of threshold has no effect on which matched pairs make it into the bucket<br>
to begin with.<br>
<br>
The matched pair (MPR) output consists of all the matched pairs that are in the buckets. So the MPR output does NOT depend on any choice of threshold value.<br>
<br>
Does that make sense?<br>
<br>
Thanks,<br>
John<br>
<div><div></div><div class="h5"><br>
Ruifang Li wrote:<br>
> Hi John,<br>
> I run point_stat tool and did two test with different fcst_thresh[] in<br>
> config file. I expect the different MPR output, but they create same MPR. I<br>
> could not figure out why. In my understanding, if fcst_thresh eq 0, fcst<br>
> value in MPR should be 0. if fcst_thresh le 100 fcst value in MPR should be<br>
> le 100, right?<br>
><br>
> Here are two fcst_thresh:<br>
><br>
> fcst_field[] =<br>
> ["UGRD/Z10","UGRD/P1000","UGRD/P925","UGRD/P850","UGRD/P700","UGRD/P500","UGRD/P400","UGRD/P300","UGRD/P250","UGRD/P200","UGRD/P150","UGRD/P100","UGRD/P70","UGRD/P50","UGRD/P30","UGRD/P20","UGRD/P10"<br>
> ];<br>
><br>
> //fcst_thresh[] = [ "le100",<br>
> "le10","le10","le100","le100","le100","le100","le100","le100","le100","le100","le100",<br>
> "le100","le100", "le100","le100","le100" ];<br>
> fcst_thresh[] = [ "eq0",<br>
> "eq0","eq0","eq0","eq0","eq0","eq0","le10","eq0","eq0","eq0","eq0",<br>
> "eq0","eq0", "eq0","eq0","eq0" ];<br>
><br>
> Here is MPR file:<br>
><br>
> /ptmp/lir/test/2009_t8_15km/verify_met2.0/test% ls -l<br>
> /ptmp/lir/data/2009_t8_15km/verify_met/gsi/point_stat/UGRD/2007081512/<br>
> total 14208<br>
> -rw-r--r-- 1 lir ncar 786984 Aug 20 16:05<br>
> point_stat_000000L_20070815_120000V.stat<br>
> -rw-r--r-- 1 lir ncar 652568 Aug 20 16:05<br>
> point_stat_000000L_20070815_120000V_mpr.txt<br>
> -rw-r--r-- 1 lir ncar 698412 Aug 20 16:05<br>
> point_stat_120000L_20070816_000000V.stat<br>
> -rw-r--r-- 1 lir ncar 579124 Aug 20 16:05<br>
> point_stat_120000L_20070816_000000V_mpr.txt<br>
> -rw-r--r-- 1 lir ncar 761574 Aug 20 16:05<br>
> point_stat_240000L_20070816_120000V.stat<br>
> -rw-r--r-- 1 lir ncar 631498 Aug 20 16:05<br>
> point_stat_240000L_20070816_120000V_mpr.txt<br>
> -rw-r--r-- 1 lir ncar 740520 Aug 20 16:05<br>
> point_stat_360000L_20070817_000000V.stat<br>
> -rw-r--r-- 1 lir ncar 614040 Aug 20 16:05<br>
> point_stat_360000L_20070817_000000V_mpr.txt<br>
> -rw-r--r-- 1 lir ncar 791340 Aug 20 16:05<br>
> point_stat_480000L_20070817_120000V.stat<br>
> -rw-r--r-- 1 lir ncar 656180 Aug 20 16:05<br>
> point_stat_480000L_20070817_120000V_mpr.txt<br>
><br>
> Script:<br>
> /ptmp/lir/test/2009_t8_15km/verify_met2.0/test% point_stat_gsi.ksh<br>
> *** Running POINT_STAT on WRF OUTPUT ***<br>
> *** UGRD ***<br>
> GSL_RNG_TYPE=mt19937<br>
> GSL_RNG_SEED=2412285258<br>
> Forecast File:<br>
> /ptmp/lir/data/2009_t8_15km/verify_met2.0/gsi/wpp/2007081512/postprd/wrfprs_d01.000<br>
> Climatology File: none<br>
> Configuration File: ./config/PointStatConfig_GSI.UGRD<br>
> Observation File:<br>
> /ptmp/lir/data/2009_t8_15km/verify_met2.0/ob_nc/2007081512/ob.nc.qc2<br>
><br>
> ----------------------------------------<br>
><br>
> Reading records for UGRD/Z10.<br>
> For UGRD/Z10 found 1 forecast levels and 0 climatology levels.<br>
><br>
><br>
> Thanks for your support,<br>
><br>
><br>
</div></div>> ------------------------------------------------------------------------<br>
><br>
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</blockquote></div><br><br clear="all"><br>-- <br>Ruifang <br><br>Mesoscale & Microscale Meteorology Division<br>Phone: 303-497-8938<br>Office: FL3-3085<br>Email: <a href="mailto:lir@ucar.edu">lir@ucar.edu</a><br>