topography plot from WRF output

[Javier G. Corripio]

This may help:


The script is for my own needs, so it does not check for any
exceptions.   If you prefer to use hgtsfc converted to pressure
instead of pressfc use the commented lines at the beginning.   The
script displays the model surface height as a grey mask across a
transect with pressure values in the Y-axis.

Best,

Javier

*plotsfc.gs  Javier.Corripio at uibk.ac.at

*'define earthg=9.80665'     ;*acceleration due to gravity (m s-2)
*'define md=28.966'           ;*molecular weight of dry air
*'define atmosr=8.31432'     ;*universal gas constant (j deg-1 kmol-1)
*'define p0=prmslmsl(lev=1013)'
*'define T0=tmpprs(lev=1013)'
*'define lrate=(tmpprs-tmpprs(lev=1013))/hgtsfc(lev=1013)'
*'define base=(T0/(T0+lrate*hgtsfc))'
*'define exponent=((earthg*md)/(atmosr*lrate*1000))'
*'define pz=p0*POW(base,exponent)'

*get gx info
'q gxinfo'
data=sublin(result,3)
px0 = subwrd(data,4)
px1 = subwrd(data,6)
data=sublin(result,4)
py0 = subwrd(data,4)
py1 = subwrd(data,6)

say px0 ' ' px1 ' ' py0 ' ' py1

*get dim info
'q dim'
data=sublin(result,4)
lev0 = subwrd(data,6)
lev1 = subwrd(data,8)

say lev0 ' ' lev1

'set lev ' lev0

*set plotting area
'set parea ' px0 ' 'px1 ' ' py0 ' ' py1

*set Yaxis range
'set vrange ' lev0 ' ' lev1

'set gxout linefill'
'set lfcols 15 15'
'set cmark 0'
'd pressfc/100;const(pressfc/100,' lev0 ')'

'set gxout line'
'set parea off'
'set lev ' lev0 ' ' lev1



On 28 Aug 2008, at 08:18, Michael J Murphy wrote:

> Grads users,
>
> I am trying to plot topography in a cross section with pressure as
> the vertical coordinate.  I have read a lot about this in the user
> archives and even found a script (orog.gs) that was written to do it.
>
> This script uses the variable psfc (press. at the surface).
> Unfortunately the variables that could be used in the script that
> are available from my WRF-ARW model output (terrain height, psfc,
> slp) are only on the lowest level.  Because of this when try:
>
> set lat 21.5
> set lev 1000 700
> d psfc
>
> The result is nothing being visibly plotted (because psfc is only
> on the lowest level).  Now if I set the vertical axis to a single
> pressure value like so:
>
> set lat 21.5
> set lev 1000
> d psfc
>
> The result is an x-y graph of the surface pressure with longitude
> on the x-axis and pressure on the y-axis.  The result is the
> similar when I try to plot terrain height and slp as well.
>
> Because psfc is only on the lowest level I cannot do the  var = lev-
> psfc/100  command.  What I really need is terrain height as a
> function of pressure!!
> Maybe someone has run into this problem with WRF output data and
> has figure this out?  Maybe I would be better off using a different
> program such as RIP?  Any advice will be greatly appreciated.
>
> Thanks,
> MJ
>
>

--
***********************************************
Javier G. Corripio
Faculty of Geo- and Atmospheric Sciences
University of Innsbruck
Innrain, 52
A-6020 Innsbruck
Austria
Tel.: +43 512 507 5418
Fax:  +43 512 507 2895
email: Javier.Corripio at uibk.ac.at
url: http://www.uibk.ac.at/geographie/personal/corripio/
http://web.mac.com/jgcorripio/
http://www.meteoexploration.com




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