[GEMPAK #YKC-319899]: RH wrt ice

> Hello,
> 
> Not sure if this is the right place for this request, but I think the 
> addition of a relative humidity with respect to ice function in gfunc would 
> be welcomed by the GEMPAK community.  I know I would find it useful.
> 
> Dave
> 
> 


Dave,

There are a number of formulations of Goff-Gratch. The WMO2000 version would 
seem to be the best
starting point unless you are researching more recent work. The es(i) 
saturation vapor pressure
with respect to ice is straight forward from temperature:
         ; WMO formulation, which is very similar to Goff Gratch
         ; Source : WMO technical regulations, WMO-NO 49, Vol I, General 
Meteorological Standards and Recommended Practices, Aug 2000, App. A.

         T0    = 273.16       ; steam point temperature in K

         Psat = 10.^(-9.09685 * (T0 / T - 1.) - 3.56654 * ALOG10(T0 / T) $
                     + 0.87682 * (1. - T / T0) + 0.78614)

I can put it on the list unless you are interested in a gemlib/df project.

Steve Chiswell
Unidata User Support 

Ticket Details
===================
Ticket ID: YKC-319899
Department: Support GEMPAK
Priority: Normal
Status: Closed