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19990311: gempak ?

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  • Subject: 19990311: gempak ?
  • Date: Mon, 15 Mar 1999 09:50:16 -0700
>From: John Egentowich <address@hidden>
>Organization: .
>Keywords: 199903111448.HAA14621

>Steve,
>I have two gempak questions for you.
>
>1.  Using gridded model output with levels every 25mb.  Is there a way in gemp
> ak
>to calculate the integrated divergence of a layer?  For example, what is the  
>   
>total divergence in the 300 to 200 layer.

John,
There is no integrating function, but you can sum the individual layers
and use the LAV (layer average) function. If you define glevel = 200:300,
then only data from those two levels would be used. If you want to
use the data from every 25 mb, then you need to calculate the divergence 
in each layer and do the summing separately.
>
>2.  Again using gridded model data.  Reference the PV in isobaric coordinates 
>   
>equation.  What is the easiest way to calculate only the second term of the   
>  
>equation (k x dv/dthte)(dthte/dp)? 
> 
You can compose all of these functions using the gempak functions in
gddiag. Is term1 v or V? If v in term 1 is the v component of the wind, 
then use VR(obs) to get the scalar in the y direction. The KCRS() function
expects a vector operand  which you would expect with KCRS(SQUO(thte,obs)).
presumably.  You can use LDF() function to compute d()/dp. You will
calculate dv/dp and dthte/dp presumably.

>
>Thanks for your help.
>
>John     
>----------------------------------
>E-Mail: John Egentowich <address@hidden>
>Date: 11-Mar-99    Time: 12:05:11
>Phone: 919-515-1444/1437
>---------------------------------
>

Steve Chiswell