[Met_help] MODE problem

John Halley Gotway johnhg at rap.ucar.edu
Tue Feb 16 14:50:36 MST 2010


Jeff,

Oops.  I sent the wrong MODE output files.  I've attached the correct ones.

Thanks,
John

> Jeff,
>
> Thanks for sending the data.  I took the Stage4 file you sent and did two
> things with it:
>
> (1) I plotted it using IDV and found that the image matches the GRADS
> image you sent.  I've attached that image from IDV.
>
> (2) Next, I ran that Stage4 file you sent through MODE, comparing it to
> itself, and found that IT TOO matches the the plots produced by IDV and
> GRADS.  I've also attached that image.
>
> I'm not sure what's going on here.  Perhaps there's been some confusion in
> file names or time stamps.  One thing I'll recommend is that you be sure
> you've downloaded all the latest patches from METv2.0 from:
>    http://www.dtcenter.org/met/users/support/known_issues/METv2.0/index.php
> Just follow the instructions at the top of the page to apply the patches.
>
> So I've attached 4 files which show plots of the data you sent.  The only
> one that doesn't match is the MODE output you sent me, which I named
> "mode_results_duda.png".  I'm guessing there was some problem in your
> script that ran MODE.
>
> Just let me know if more questions come up.
>
> Thanks,
> John
>
>> John,
>> Apparently I'm not experienced enough with IDV to know how to plot the
>> data
>> myself, so I'll ask you to do it.  I uploaded two files to the server.
>> The
>> one named ST4.2009050804.01h.regrid is the Stage IV data (1 hour
>> precip).
>> The one named 04Z-03Z is the netCDF file output from pcp_combine.  It is
>> from my WRF simulation and should hold just 1-hr precip as a variable.
>> Thanks for looking into this for me.
>>
>> Jeff
>>
>> On Tue, Feb 16, 2010 at 9:26 AM, John Halley Gotway <johnhg at ucar.edu>
>> wrote:
>>
>>> Jeff,
>>>
>>> Sorry for the delay in getting back to you.  I was out of the office
>>> last
>>> week.
>>>
>>> I took a look at the images you sent, and I do see the offset you're
>>> describing.  And I also looked at the composite reflectivity field for
>>> the
>>> 04Z May 8, 2009 case and see how it lines up with the
>>> GRADS image you're producing.  I'm not sure what's going on here.  But
>>> I
>>> have a couple of thoughts...
>>>
>>> (1) You're welcome to create a color table for MODE to use to more
>>> closely
>>> match the GRADS one you're using.  The easiest thing to is to use the
>>> default one but set min/max values for it.  By default,
>>> MODE will scale the colortable to use the min/max data values in the
>>> field
>>> it's plotting.  So the colortable will change each time you run MODE.
>>> You
>>> can manually set the range for the colortable in
>>> the MODE config file using the following parameters:
>>>   fcst_raw_plot_min, fcst_raw_plot_max, obs_raw_plot_min,
>>> obs_raw_plot_max
>>> You're also welcome to create a new colortable and point to it using
>>> the
>>> config file parameters:
>>>   fcst_raw_color_table, obs_raw_color_table
>>>
>>> (2) The problem is basically that MODE and GRADS are not rendering the
>>> raw
>>> data in the same way.  Could we try plotting it with a third tool?  I'd
>>> suggest using IDV, a nice plotting tool put out by
>>> Unidata:
>>> http://www.unidata.ucar.edu/software/idv/
>>> If you've never used IDV before, I'd be happy to plot it up with IDV.
>>> But
>>> I'd need the raw data files you're using.  If you'd like to send those
>>> to
>>> me, you can post them to our anonymous FTP site:
>>>
>>> ftp ftp.rap.ucar.edu
>>> username = anonymous
>>> password = "your email address"
>>> cd incoming/irap/met_help/duda_data
>>> put "your data files"
>>> bye
>>>
>>> It would be nice to take a look at the data files you're using.  It may
>>> expose a bug in the MET grid or plotting code.   Or it may be a problem
>>> in
>>> how the grid it defined in the data.
>>>
>>> Thanks,
>>> John
>>>
>>> Jeffrey Duda wrote:
>>> > John,
>>> > I am experiencing a problem with MODE.  I am sending you several
>>> files
>>> to
>>> > show you the problem.  Three of them are Grads images showing 1-hr
>>> > accumulated precip from Stage IV data (observation).  The other three
>>> are
>>> > the post script files from MODE for the same days as the three Grads
>>> > images.  The dates are:
>>> >
>>> > 08 May 2009 (ending at 04 UTC)
>>> > 19 July 2008 (ending at 18 UTC)
>>> > 22 May 2007 (ending at 21 UTC)
>>> >
>>> > The problem is that MODE is displacing the observed precipitation
>>> objects
>>> > some distance away from where they really are.  This can be seen by
>>> > comparing the Grads images for the May cases against the images found
>>> on
>>> > page 3 of the post script files.  It seems to be mostly an eastward
>>> > displacement of around 0.5 to 1 degree longitude, and a slight
>>> northward
>>> > displacement.  Strangely, this error does not seem to occur in the
>>> July
>>> case
>>> > (or if it does, it is of such a small magnitude that I can't tell).
>>> I
>>> > believe the Grads images to be correct because I have spent time
>>> viewing
>>> > archived reflectivity for these cases (a good source for viewing it
>>> would
>>> be
>>> > at www.mmm.ucar.edu/imagearchive...then just adjust the parameters to
>>> the
>>> > correct year/month/day, and view either Central Plains sector or
>>> Northern
>>> > Plains sector for the July case to view the reflectivity), and the
>>> > associated precipitation seems to line up pretty well with the
>>> archived
>>> > reflectivity.  Thus, I don't think it's an error on the part of
>>> Grads.
>>>  My
>>> > adviser Bill Gallus believes it has something to do with the way the
>>> > projections assign various points to each other in MODE.  Please
>>> help.
>>>  If
>>> > you need any more images or files to show you this, please let me
>>> know.
>>> > Thanks.
>>> >
>>> > Jeff Duda
>>> >
>>> >
>>> >
>>> > ------------------------------------------------------------------------
>>> >
>>> >
>>> > ------------------------------------------------------------------------
>>> >
>>> >
>>> > ------------------------------------------------------------------------
>>> >
>>>
>>
>>
>>
>> --
>> Jeff Duda
>> Iowa State University
>> Meteorology Graduate Student
>> 3134 Agronomy Hall
>> www.meteor.iastate.edu/~jdduda
>>
>
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