[gradsusr] LFC calculation

[Kevin Huyck]

Meredith,

I ran into a similar problem while attempting to compute condensation 
pressure deficit (CPD). My solution was to derive an equation for my 
value of interest and then implement it in GrADS. Deriving the equation 
was the most difficult portion of this task. Once I had that in hand, I 
used several steps to bootstrap the solution in GrADS. For example, my 
CPD equation requires virtual temperature and the change in height by 
way of the hypsometric equation. For one step, I calculate the virtual 
temperature grid. In the next step I use the calculated virtual 
temperature grid in the hypsometric equation to find the change in 
height. For my way of thinking, a step-wise process, taking each piece 
in a small chunk, is easiest to comprehend during the testing phase. 
After you verify your solution works, you can refine the method to 
improve your processing efficiency.

In my experience, you can "define [var]=[eqn]" to create the appropriate 
gridded variable. If you have x and y varying (for a single time), 
you'll calculate the variable for each gridpoint in your domain or vary 
x, y, and t for multiple time steps in your domain.

Hope this helps.

-- 
Kevin L. Huyck
Forecaster, Meridian Environmental Technology, Inc.
klhuyck at meridian-enviro.com <mailto:klhuyck at meridian-enviro.com>

Composed using Mozilla Thunderbird!


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Hi Everyone,

I'm looking to plot a contour plot of LFC height, similar to the graphic
on the SPC Mesoscale Analysis page, my control file does not output LFC
directly,  is there anyway I can calculate this in grads?

Thanks for your help.

Meredith
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