[Wrf-users] Wrf-users Digest, Vol 99, Issue 23

[Hein Zelle]

Wen wrote:

> Hi all. The upper air temperature is perturbation potential
> temperature (theta-t0) in the output from wrf.exe. I want to obtain
> the actual air temperature. I am really understand the perturbation
> potential temperature and don't know how to transform it into actual
> air temperature on pressure level. What should I do if I use NCL to
> write the code? I hope you can help. Thanks! 

In the WRF manual you can find how to convert from perturbation values
to full temperature (K) (page 5-79 of the 3.4 manual).  This also
lists several other commonly required variables.

Total potential temperature (K) = T + 300

We convert potential temperature to actual air temperature with the
following equation (most meteorology text books should have this):

p_ref = 100000
kappa = 0.2854
temp (K) = (theta / ((p_ref / full_pressure)^kappa))


Kind regards,
     Hein Zelle



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Dr. Hein Zelle
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