specific humidity

Any WPS problems/questions that might not fall into the other topics in this category

specific humidity

Postby mmeclimate » Mon Nov 17, 2008 9:09 am


I am creating my own intermediate files and I was wondering whether I can use specific humidity instead of relative humidity. I know that WRF needs relative humidity as input, but I read somewhere that WRF calculates the RH if the input is the SH.
If I can use SH, what is the specific humidity metgrid name (e.g.: the skin temperature metgrid name is SKINTEMP)?

Posts: 7
Joined: Fri Nov 07, 2008 3:35 pm

Re: specific humidity

Postby pmoreira » Thu Jun 24, 2010 3:35 pm

I just needed this and came here for an answer...Since I couldn't find one, I'll leave one here.

In case anyone ever needs it http://www.mmm.ucar.edu/wrf/OnLineTutor ... fields.htm
Posts: 18
Joined: Wed Mar 03, 2010 7:13 pm

Re: specific humidity

Postby hmk1001 » Tue Jul 19, 2011 2:09 am

RH calculated from specific humidity, pressure and temperature.
My source code excerpted parts of ungrib code.


real, parameter :: svp1=611.2
real, parameter :: svp2=17.67
real, parameter :: svp3=29.65
real, parameter :: svpt0=273.15
real, parameter :: eps = 0.622

do ktime=1,ntime !hwang
field_data(i3d_RH,:,:,:,KTIME) = 1.E2 * &
(p (:,:,:)*field_data(i3d_Q,:,:,:,KTIME) /(field_data(i3d_Q,:,:,:,KTIME) *(1.-eps) + eps)) &
end do

Good luck..
Posts: 2
Joined: Thu Jan 06, 2011 11:55 am

Re: specific humidity

Postby k3zuya » Sun Oct 30, 2011 7:13 am

Can I calculate the additional information such as wind speed etc?
Posts: 1
Joined: Sun Oct 30, 2011 7:07 am

Re: specific humidity

Postby mkaraca » Sat Mar 16, 2013 7:18 pm


Are these coefficients (svp1, svp2..) taken from the source (Tmin=180. K, Tmax=330. K).

Is it possible to compile the post processing lines with module_mp_HWRF.F(?).

Posts: 5
Joined: Mon Mar 19, 2012 12:06 pm

Return to Miscellaneous

Who is online

Users browsing this forum: No registered users and 1 guest