[gradsusr] Computing the vertical velocity by the omega equation

[Jeffrey Duda]

Jose,
I do not have a script that will use the omega equation, but the kinematic
method uses vertically integrated divergence, which is very simple to
implement:

'define omega = vint(psfc,hdivg(u,v),500)'

The above example assumes
1) you have data on pressure surfaces
2) the variable representing surface pressure is psfc
3) the variables representing the horizontal wind components are u and v
4) you want to find omega at 500 mb
5) you have no vertical velocity at the surface

Given the simplicity of this method, it can give errant results, but the
general pattern should be represented.  To make the kinematic method a
better approximation, you can use the methods in O'Brien
(1970).<http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2008/pdfNwIUpObZBI.pdf>

Hope this helps.

Jeff Duda

On Wed, Aug 31, 2011 at 4:08 PM, veiga <veiga.uea at gmail.com> wrote:

> Dear GrAds users,
>
> Is there someone who knows where I can find a GrAds script which computes
> the vertical velocity through  the omega equation?
> Other methods like kinematic, adiabatic and quase-geostrophic relative
> vorticity, are welcome as well.
>
> Any hint will be very appreciated.
>
> Cheers,
>
> José Augusto P. Veiga,
>
> ======================================
> Universidade do Estado do Amazonas
> Departamento de Meteorologia
> Escola Superior de Tecnologia (EST)
>
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-- 
Jeff Duda
Iowa State University
Meteorology Graduate Student
www.meteor.iastate.edu/~jdduda <http://www.meteor.iastate.edu/%7Ejdduda>
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