Re: precipitable water

One approach

[1]
http://www.ncl.ucar.edu/Document/Functions/Built-in/dpres_hybrid_ccm.shtml

This uses:
    p(k) = A(k)*PO + B(k)*PS
The B(k) are the the sigma levels.
    A = sigma
    A = 0.0
    P0 = 0.0
    dp_sigma = dpres_hybrid_ccm(ps,P0,A,sigma)
    dp_sigma!0 = ps!0 ; (say) time
    dp_sigma!1 = "plevel"
    dp_sigma!2 = ps!1 ; lat
    dp_sigma!3 = ps!2 ; lon
    printVarSummary(dp_sigma)

[2]
http://www.ncl.ucar.edu/Document/Functions/Built-in/prcwater_dp.shtml
   pw =
prcwater_dp(q(time|:,lat|:,lon|:,sigma|:),dp_sigma(time|:,lat|:,lon|:,plevel|:))

   pw@long_name = "total column precipitable water"
   pw@units = "kg/m2"

On 02/22/2011 02:36 PM, Michael Notaro wrote:
> How can I compute precipitable water
> on a lat2d x lon2d grid using sigma
> coordinates, given water vapor mixing
> ratio output and surface pressure?
>
> Thanks, Michael
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk

-- 
======================================================
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 |
======================================================
_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk