[gradsusr] Plotting EP Fluxes in GrADS

[Jeff Duda]

Yes, I mean, type 'd skip(epy,2,1);skip(-epz,2,1).  I've used such a tactic
to make 2D wind vectors appear to go up for negative omega values.

Jeff

On Thu, Sep 6, 2012 at 8:08 AM, Jason Furtado <jfurtado at aer.com> wrote:

>  Do you mean insert a '-' on the flux: d skip(epy,2,1);skip(-epz,2,1)
>
> If not, how do you flip the sign of the vertical coordinate (note: I still
> want pressure to descend upwards and be on a log scale)?
>
> - Jason
>
>
> On 9/5/12 5:19 PM, Jeff Duda wrote:
>
> What about just flipping the sign of the vertical coordinate in the
> display command? If you do that, do the vectors match up?
>
>  Jeff
>
> On Wed, Sep 5, 2012 at 3:31 PM, Jason Furtado <jfurtado at aer.com> wrote:
>
>> All -
>>
>> I am running into an issue with plotting EP flux vectors on the
>> latitude-by-pressure plane in GrADS.  I did the calculations in another
>> language and wrote out relevant data (EPy, EPz, and the divergence of
>> the flux) to a binary file to load and plot in GrADS.   I have checked
>> my plot against a plot that I can generate on the NCEP website and the
>> vertical direction of the arrows is reversed (they point down in the
>> GrADS plot but should point up according to the NCEP plot).
>>
>> Having checked the values plotted in GrADS (using gxout grid), many of
>> the values of EPz are negative.  According to the Edmon et al. (1980)
>> paper, in pressure coordinates, positive (negative) EPz should point
>> toward higher (lower) pressure.  Is this an issue with GrADs?  Anyone
>> else run into this issue?  My (abbreviated) script is below.
>>
>> reinit
>> set background 1
>>
>> open epfluxes_epdiv_2009_2010_obs.ctl
>>
>> set t 390 390
>> set lat 10 90
>> set vpage 0 11 0 6
>> set annot 0
>>
>> set gxout vector
>> set zlog on
>> set z 1 17
>> set xaxis 10 90 10
>> set xlabs 10N|20N|30N|40N|50N|60N|70N|80N|90N|
>> set ylevs 10 50 100 300 500 1000
>> set grads off
>> set grid off
>> set font 1
>> set ylopts 0 4 0.2
>> set xlopts 0 4 0.2
>>
>> set arrscl 1 200
>> set ccolor 2
>> set cthick 6
>> set arrowhead -0.25
>> set arrlab on
>> set grid off
>> d skip(epy,2,1);skip(epz,2,1)
>>
>> Thanks!
>> - Jason
>> --
>> Jason C. Furtado, Ph.D.
>> Staff Scientist
>> Atmospheric and Environmental Research (AER), a Verisk Analytics company
>> 131 Hartwell Ave.
>> Lexington, MA 02421
>>
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>>
>
>
>
>  --
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
>
>
>
> _______________________________________________
> gradsusr mailing listgradsusr at gradsusr.orghttp://gradsusr.org/mailman/listinfo/gradsusr
>
>
> --
> Jason C. Furtado, Ph.D.
> Staff Scientist
> Atmospheric and Environmental Research (AER), a Verisk Analytics company
> 131 Hartwell Ave.
> Lexington, MA 02421
>
> E-mail:  jfurtado at aer.com
> Phone:  781-761-2384
>
>
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> gradsusr at gradsusr.org
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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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