## specific humidity

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

### specific humidity

Hi,

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)?
Thanks,

Michael
mmeclimate

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

### Re: specific humidity

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
pmoreira

Posts: 18
Joined: Wed Mar 03, 2010 7:13 pm

### Re: specific humidity

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)) &
/(svp1*exp(svp2*(field_data(i3d_TT,:,:,:,KTIME)-svpt0)/(field_data(i3d_TT,:,:,:,KTIME)-svp3)))
end do

=======================================================================
Good luck..
hmk1001

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

### Re: specific humidity

Can I calculate the additional information such as wind speed etc?
k3zuya

Posts: 1
Joined: Sun Oct 30, 2011 7:07 am

### Re: specific humidity

hi,

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(?).

Thanks,
Mehmet
mkaraca

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

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