[gradsusr] Plotting a NEXRAD netCDF file

Sat Sep 21 09:25:57 EDT 2013

Thank you, I saw that the grid resolutions works, now I will try out the
regrid option also.

Sytske

Sytske (seets-kah) Kimball
Professor of Meteorology
Director, South Alabama Mesonet
Dept. of Earth Sciences
University of South Alabama
Mobile, AL
phone (251) 460-7031
fax       (251) 460-7886
email   skimball at southalabama.edu <skimball at usouthal.edu>
web:   http://chiliweb.southalabama.edu/

On Fri, Sep 20, 2013 at 5:22 PM, Andrew Revering <andy at f5data.com> wrote:

> When you create the netcdf,  make sure the resolution is very large. Im
> mobile right now so i cant check my code but try something like 1000 or
> even 12000.... I dont recall how big is big enough to capture the data,
> but you can re-run it and experiment.
>
> The other thing is the resolution of the grid in grads. I use a regrid
> function at very high resolution. I think its something like...
>
> Re(dbz, 0.0018)
>
> Again the order of magnitude may be off by 10 as im not in front of my
> code right now.
> On Sep 20, 2013 4:32 PM, "Sytske Kimball" <skimball at southalabama.edu>
> wrote:
>
>> It was level2 and I tried setting the Grid Cell Size in NOAA's WCT to a
>> finer resolution than the default value. That did the trick!!
>>
>> Sytske
>>
>>
>>
>> Sytske (seets-kah) Kimball
>> Professor of Meteorology
>> Director, South Alabama Mesonet
>> Dept. of Earth Sciences
>> University of South Alabama
>> Mobile, AL
>> phone (251) 460-7031
>> fax       (251) 460-7886
>> email   skimball at southalabama.edu <skimball at usouthal.edu>
>> web:   http://chiliweb.southalabama.edu/
>>
>>
>>
>> On Fri, Sep 20, 2013 at 3:39 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> Specifically which product did you convert?  Was it level 2 or level 3
>>> data?
>>>
>>> Jeff Duda
>>>
>>>
>>> On Fri, Sep 20, 2013 at 3:34 PM, Sytske Kimball <
>>> skimball at southalabama.edu> wrote:
>>>
>>>> Jennifer,
>>>>
>>>> I agree. Not sure how that happened. I used NOAA's Weather and Climate
>>>> Toolkit to convert the radar data to netCDF so maybe something went amiss
>>>> in that process.
>>>>
>>>> Thanks for your help,
>>>> Sytske
>>>>
>>>>
>>>> Sytske (seets-kah) Kimball
>>>> Professor of Meteorology
>>>> Director, South Alabama Mesonet
>>>> Dept. of Earth Sciences
>>>> University of South Alabama
>>>> Mobile, AL
>>>> phone (251) 460-7031
>>>> fax       (251) 460-7886
>>>> email   skimball at southalabama.edu <skimball at usouthal.edu>
>>>> web:   http://chiliweb.southalabama.edu/
>>>>
>>>>
>>>>
>>>> On Fri, Sep 20, 2013 at 3:25 PM, Jennifer Adams <jma at cola.iges.org>wrote:
>>>>
>>>>>
>>>>> On Sep 20, 2013, at 4:17 PM, Sytske Kimball wrote:
>>>>>
>>>>> Jennifer,
>>>>>
>>>>> Thanks for your response. Replies are added in below.
>>>>>
>>>>>
>>>>> On Fri, Sep 20, 2013 at 3:03 PM, Jennifer Adams <jma at cola.iges.org>wrote:
>>>>>
>>>>>>
>>>>>> On Sep 20, 2013, at 3:47 PM, Andrew Friedman wrote:
>>>>>>
>>>>>> Hi Sytske,
>>>>>>
>>>>>> In your script you have 2 plot settings right after each other:
>>>>>>
>>>>>> 'set gxout grfill'
>>>>>> 'set gxout shaded'
>>>>>>
>>>>>> I believe the second one overrides the first. Try commenting it out
>>>>>> to see what the grfill plot looks like.
>>>>>>
>>>>>> That's right -- grfill will give a better view of actual grid box
>>>>>> size. What does 'q ctlinfo' give you after you invoke sdfopen?
>>>>>>
>>>>>
>>>>> The plot with 'set gxout shaded' commented out, is attached - not very
>>>>> nice looking...….
>>>>>
>>>>> True, but that pixelated nature of the data explains why your shaded
>>>>> plot looked even worse.
>>>>>
>>>>>  'q ctlinfo' came back with the following:
>>>>>
>>>>> dset KMOB_V03_20091110_035730.nc
>>>>> title Nexrad 2 radar dataset  03:57:30 UTC  11/10/2009
>>>>> undef -999
>>>>> dtype netcdf
>>>>> xdef 800 linear -127.06 0.0776505
>>>>> ydef 490 linear 20.4756 0.0776505
>>>>>
>>>>> Which is about an 8km grid. I'm guessing the radar data is much higher
>>>>> resolution than that.
>>>>> --Jennifer
>>>>>
>>>>>
>>>>>
>>>>> zdef 1 linear 0 1
>>>>> tdef 1 linear 03:57Z10NOV2009 1mn
>>>>> vars 1
>>>>> Reflectivity=>reflectivity  0  t,y,x  Nexrad 2 radar dataset
>>>>> endvars
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>> Also, you could try changing the shaded plot setting to the
>>>>>> higher-resoluttion algorithm:
>>>>>> 'set gxout shade2b'
>>>>>>
>>>>>> shade2b is not higher resolution -- it has more smaller polygons and
>>>>>> takes longer to render. shade2 and shade2b should look exactly the same.
>>>>>>
>>>>>
>>>>> 'set gxout shaded' and 'set gxout shade2' look the same.
>>>>>
>>>>> Sytske
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>  --Jennifer
>>>>>>
>>>>>>
>>>>>> Andrew
>>>>>>
>>>>>> On Sep 20, 2013, at 12:23 PM, Sytske Kimball <
>>>>>> skimball at southalabama.edu> wrote:
>>>>>>
>>>>>> Dear GrADS users,
>>>>>>
>>>>>>
>>>>>> I (finally) managed to plot a NEXRAD radar reflectivity fil, in
>>>>>> netCDF format, using GrADS. The plot is attached (IdaRadar-test.png) as is
>>>>>> the original radar image for the same area, displayed using GRLevelII
>>>>>> (RadarLevel2.png). I can't figure out why the resolution on the GrADS image
>>>>>> is so much worse than on the original image. The script is also attached.
>>>>>>
>>>>>>
>>>>>> Any help would be much appreciated.
>>>>>>
>>>>>>
>>>>>> Thank you in advance,
>>>>>>
>>>>>> Sytske
>>>>>>
>>>>>>
>>>>>> Sytske (seets-kah) Kimball
>>>>>>
>>>>>> Professor of Meteorology
>>>>>>
>>>>>>  Director, South Alabama Mesonet
>>>>>>
>>>>>> Dept. of Earth Sciences
>>>>>>
>>>>>> University of South Alabama
>>>>>>
>>>>>> Mobile, AL
>>>>>>
>>>>>> phone (251) 460-7031
>>>>>>
>>>>>> fax       (251) 460-7886
>>>>>>
>>>>>> email   skimball at southalabama.edu
>>>>>>
>>>>>> web:   http://chiliweb.southalabama.edu/
>>>>>>
>>>>>> <RadarLevel2.png><IdaRadar-test.png><StationPlot+radar2.gs
>>>>>> >_______________________________________________
>>>>>>
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>>>>>>
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>>>>>>
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>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>>
>>>>>>
>>>>>>  --
>>>>>> Jennifer M. Adams
>>>>>> Center for Ocean-Land-Atmosphere Studies (COLA)
>>>>>> 111 Research Hall, Mail Stop 2B3
>>>>>> George Mason University
>>>>>> 4400 University Drive
>>>>>> Fairfax, VA 22030
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>>>>>
>>>>>>
>>>>> <IdaRadar-test2.png>_______________________________________________
>>>>> gradsusr mailing list
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>>>>>
>>>>>
>>>>>  --
>>>>> Jennifer M. Adams
>>>>> Center for Ocean-Land-Atmosphere Studies (COLA)
>>>>> 111 Research Hall, Mail Stop 2B3
>>>>> George Mason University
>>>>> 4400 University Drive
>>>>> Fairfax, VA 22030
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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>>>>>
>>>>
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>>>
>>>
>>> --
>>> Jeff Duda
>>> Graduate research assistant
>>> University of Oklahoma School of Meteorology
>>> Center for Analysis and Prediction of Storms
>>>
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>>>
>>
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