RE: ageostrophic component from operational (u,v) fwind ields

_From William.Fingerhut@xxxxxxxxxxx  Fri Dec  8 08:44:15 2006
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I have a cludgy jython method that computes geostrophic wind,
which one could easily modify or 'use' to compute the ageostrophic wind.

To use it, I first select a dataset (model data);=20

then use a formula: geoWind(height_grid)

which uses the jython method:


#
# geostrophic wind
#
def geoWind(h):
  from ucar.unidata.data.grid.DerivedGridFactory import *
  z=3D0.*h
  o=3Dz-1
  vg=3D100.*DerivedGridFactory.createHorizontalAdvection(h,o,z)
  ug=3D-100.*DerivedGridFactory.createHorizontalAdvection(h,z,o)
  return DerivedGridFactory.createTrueWindVectors(ug,vg)


The constant 100 includes the correct constant for the geostrophic wind,
a constant latitude, and a scaling factor. The constants, 0 and 1, allow
me
to use the existing code to calculate each partial derivative of height.

If anyone has another method, I would like to hear about it.

Bill

< Bill Fingerhut, Professor           PHONE: 802-626-6257 >
< Meteorology Dept                    FAX:   802-626-9770 >
< Lyndon State College                                    >
< Lyndonville, Vt 05851                                   >
<                                                         >
< EMAIL:     william.fingerhut@xxxxxxxxxxxxxxx            >
<            bfingerhut@xxxxxxxxxxxxxxxx                  >
< WWW:       http://apollo.lsc.vsc.edu/ <http://apollo.lsc.vsc.edu/>
>
<                                                         >
< disclaimer: I know nothing - I only work here.          >


> -----Original Message-----
> From: owner-idvusers@xxxxxxxxxxxxxxxx
> [mailto:owner-idvusers@xxxxxxxxxxxxxxxx
<mailto:owner-idvusers@xxxxxxxxxxxxxxxx> ] On Behalf Of HansPeter Roesli
> Sent: Thursday, December 07, 2006 4:31 PM
> To: IDV Users' Mailing List
> Subject: ageostrophic component from operational (u,v) fwind ields
>
>
> Hi all
>
> I would like to draw flow fields of the ageostrophic component of
> numerical (u,v) wind fields. Anybody out there who has already
> implemented this in some way. I would be very grateful in
> receiving some
> information.
>
> HansPeter Roesli
> consultant to EUMETSAT in satellite meteorology
>


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