[gradsusr] Computing the vertical velocity by the omega equation

[veiga]

Hi Jeff, 

I appreciated your help, mainly cause you gave a important hint into the computation of vertical velocity via kinematic method. It seems to be a nice way to follow. You're right! However, as this method is very simple, we should worry about errors implicated in. This is the cause I should compute the vertical velocity (or pressure velocity in units of mb/s) using the omega equation. Furthermore, I need to calculate it in a 3-D spatial domain instead of in one single level.  

Thank you very much Jeff.

 I'll keep waiting for other hints and help. 

Cheers,

José Augusto P. Veiga, 

======================================
Universidade do Estado do Amazonas 
Departamento de Meteorologia
Escola Superior de Tecnologia (EST)
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Av. Darcy Vargas, 1200, Manaus-AM Brasil
Work phone:    (92) 3878 4333
Cell   phone :    (92) 8196 7122
Skype: veiga_j.a.p.
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CV: http://lattes.cnpq.br/4027612512091565
URL:http://scientificmet.wordpress.com/
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On Aug 31, 2011, at 5:22 PM, Jeffrey Duda wrote:

> 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).
> 
> 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)
> -----------------------------------------------------------------------------
> Av. Darcy Vargas, 1200, Manaus-AM Brasil
> Work phone:    (92) 3878 4333
> Cell   phone :    (92) 8196 7122
> Skype: veiga_j.a.p.
> -----------------------------------------------------------------------------
> CV: http://lattes.cnpq.br/4027612512091565
> URL:http://scientificmet.wordpress.com/
> -----------------------------------------------------------------------------
> 
> 
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> 
> 
> -- 
> Jeff Duda
> Iowa State University
> Meteorology Graduate Student
> www.meteor.iastate.edu/~jdduda
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