[Met_help] Re: MET error
Lacey Holland
lholland at ucar.edu
Mon Oct 8 14:24:15 MDT 2007
Hi, Luke!
Just reading through the description of that prepbufr dataset, it looks
like an excellent archive data source to use for verifying model runs in
non-CONUS regions. I think it's been quality-controlled by the GFS
analysis, so it should work great for your purposes. Nice find!
Thanks for passing this along!
--Lacey Holland
John Halley Gotway wrote:
> Luke,
>
> The accumulation interval is meant for precipitation fields. If you use a utility like 'wgrib' to dump the contents of a grib file you may find precipitation fields with different accumulation
> intervals. For example, a single grib file may contain accumulated precipitation (APCP or grib code 61) with accumulation intervals of 1 hour and 24 hours. So specifying "61/A24" or equivalently
> "APCP/A24" would select out the 24 hour accumulated precip field.
>
> I suppose you could try to use point_stat to compare precip to gauge data, but I'm really not sure if gauge data is available in the PrepBufr files. If you'd like to compare gridded precip to gridded
> observations like StageII or StageIV analysis, you could use the grid_stat or mode tools.
>
> As for the observation files, in the MET beta release we're only supporting point observation data in PrepBufr format. We realize that this is a limitation, and we've received requests from users to
> support additional point observation formats. We'll be adding support for the ObsProc (formatted ascii) observation format used by data assimilation folks in the near future. And we may add support
> for additional observation formats based on user feedback.
>
> I do know that the PrepBufr data available from NCEP contains observations from outside of CONUS. But as for the appropriateness of using the NCDC data, I'll defer to a scientist in our group, Lacey
> Holland, who I've copied on this email.
>
> Thanks,
> John
>
> Luke Peffers wrote:
>
>> Hello John, I have a couple quick questions for you regarding my ongoing MET
>> experimentation:
>>
>> In the MET point_stat config file, there is an option for comparing
>> observations of accumulation intervals (i.e. ANNN). I am unclear as to what
>> the accumulation interval should be set to for comparing various
>> observations. What could this be used for and how does one determine what
>> to set the interval, ANNN, to?
>>
>> Also, I am interested in WRF verification in non CONUS regions of the
>> world. I have found a PREPBUFR dataset from NCDC (DSI-6116
>> http://www1.ncdc.noaa.gov/pub/data/documentlibrary/tddoc/td6116.pdf ) ,
>> which I hope will include enough observations to make a sound statistical
>> comparison with my WRF run. I would like to know if you are aware of any
>> other global datasets that can be used with MET point-stat and if not, what
>> do you think of a dataset such as the above mentioned?
>>
>> Thank you for all your time and assistance.
>>
>> Luke Peffers
>> FSU
>>
>> On 10/5/07, Luke Peffers <luke.peffers at gmail.com> wrote:
>>
>>> Thanks John, I realized that there may be an issue with sample size since
>>> I am trying to verify at 6Z. I now know to use the most robust sounding
>>> data which is included in the 00Z and 12Z obs. My mistake, but I'm glad my
>>> amateurism is contributing to your work! I'm happy to help.
>>>
>>> Luke
>>>
>>>
>>> On 10/5/07, John Halley Gotway <johnhg at rap.ucar.edu> wrote:
>>>
>>>> Luke,
>>>>
>>>> This is good stuff. I'm glad you caught this error. What's happening
>>>> is that we're computing statistics for a sample size of only 1! When we go
>>>> to compute confidence intervals, needless to say,
>>>> there are problems. I've added checks to only compute confidence
>>>> intervals when the sample size is large enough to do so.
>>>>
>>>> However, we're leaving it up to the users to interpret their
>>>> results. For example, if you have a confidence interval computed for a very
>>>> small sample size (under 10), I wouldn't trust it very much.
>>>>
>>>> I've attached an updated version of the file "point_stat.cc". You can
>>>> use it to replace the version in METv0.9/src/point_stat. Then at the
>>>> top-level, do a "make clean" followed by a "make >&
>>>> make_met.log".
>>>>
>>>> Let me know if you run into other problems. I'll include these changes
>>>> in the development version of MET so that they appear in the next official
>>>> release.
>>>>
>>>> Thanks for finding this bug Luke. We really appreciate it.
>>>>
>>>> John
>>>>
>>>> Luke Peffers wrote:
>>>>
>>>>> Ok John, I have "put" the data you requested in your directory via
>>>>>
>>>> ftp. As
>>>>
>>>>> for the point_stat statement, I did enter it correctly but goofed when
>>>>>
>>>> I
>>>>
>>>>> typed the email. Too bad that wasn't the only problem. Please let me
>>>>>
>>>> know
>>>>
>>>>> what you find.
>>>>>
>>>>> Luke Peffers
>>>>> FSU
>>>>>
>>>>> On 10/4/07, John Halley Gotway <johnhg at rap.ucar.edu> wrote:
>>>>>
>>>>>> Luke,
>>>>>>
>>>>>> I haven't seen that error message before. One thing to point out
>>>>>> though... If you look at the usage statement for point_stat, you'll
>>>>>>
>>>> see
>>>>
>>>>>> that it's expecting the "model" name to be listed as the 3rd
>>>>>>
>>>> argument. So
>>>>
>>>>>> you should running the command as:
>>>>>> /point_stat ./WRFPRS_d01.72 ./OBS_10_01_06.nc WRF_SingleG -config
>>>>>> PointStatConfig_default
>>>>>>
>>>>>> Otherwise, it'll think the model name is "-config". I should
>>>>>>
>>>> probably
>>>>
>>>>>> make the argument processing smarter than that to skip the optional
>>>>>> arguments.
>>>>>>
>>>>>> Anyway, I'm guessing I'll need to run the data you're using to try to
>>>>>> reproduce the error. Would you be able to post those files to the
>>>>>>
>>>> FTP
>>>>
>>>>>> site again?
>>>>>>
>>>>>> I'd need the 3 files:
>>>>>> WRFPRS_d01.72
>>>>>> OBS_10_01_06.nc
>>>>>> PointStatConfig_default
>>>>>>
>>>>>> Please let me know when they're up there, and I'll give it a shot.
>>>>>>
>>>>>> Thanks,
>>>>>> John
>>>>>>
>>>>>>
>>>>>>> Hello John:
>>>>>>>
>>>>>>> I have another error for you. I received this one with this
>>>>>>>
>>>> command:
>>>>
>>>>>>> ./point_stat ./WRFPRS_d01.72 ./OBS_10_01_06.nc -config
>>>>>>> ./PointStatConfig_default WRF_SingleG
>>>>>>>
>>>>>>> gsl: beta.c:56: ERROR: domain error
>>>>>>> Default GSL error handler invoked.
>>>>>>> Abort
>>>>>>>
>>>>>>> Do you know where things may have gone wrong?
>>>>>>>
>>>>>>> Luke Peffers
>>>>>>> FSU
>>>>>>>
>>>>>>>
--
____________________________
Lacey Holland
UCAR/NCAR, Research Applications Laboratory
P.O. Box 3000
Boulder, CO 80307
(303) 497-8396
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