[Met_help] MODE problem

Tue Feb 16 14:45:52 MST 2010

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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