[RegCNET] Dew point

[Neil Davis]

I am trying to calculate dewpoint for RegCM3 and just wanted to make 
sure that my calculation was correct, I found a conversion on the 
internet and wasn't sure that it would be correct.  This is how I am 
calculating it.

vmr = qv*1000*(28.9644/18.01534)
ph2o = vmr/1000*Pressure Level
mil = 2.5*10^6
p1=1/273
td1 = (p1-(461/mil*(log(ph2o/6.11))))
td=td1^ -1

where qv is the models specific humidity and the pressure level is taken 
from the ctl file's value for a given z value in grads. 

Thank you for your help
Neil Davis