Re: Lookin' for a function

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Wed, 04 Mar 2009 13:18:41 -0700

I do not know if WRF has a preferred equation but, I think,
all you need is temperature. Take a look at:

http://cires.colorado.edu/~voemel/vp.html

Many of these are of the form
    log(pw) = ...

You will have to modify slightly to return pw

The simplest is Bolton's formula:
   pw = 6.112 exp(17.67 * t / (t+243.5) ) ; t in degC ; pw will be hPa
===================
You can check answers against
    http://www.s-ohe.com/Water_cal.html
Good luck
D
Gerry Creager wrote:
> Does anyone already have a canned function to calculate water vapor
> pressure from WRF output? If not, it appears trivial to write, but
> there's no sense writing it if someone else already has!
>
> gerry
>

-- 
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Dennis J. Shea                  tel: 303-497-1361    |
P.O. Box 3000                   fax: 303-497-1333    |
Climate Analysis Section                             |
Climate & Global Dynamics Div.                       |
National Center for Atmospheric Research             |
Boulder, CO  80307                                   |
USA                        email: shea 'at' ucar.edu |
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Received on Wed Mar 04 2009 - 13:18:41 MST

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