[Wrf-users] perturbation potential temperature

[Liu, Peng]

Dear Users,
I ran two data set by WRF and want to compare the predicted temperature. The output temperature of WRF is perturbation potential temperature, So I have a few questions.

First, how WRF sets the reference sea level temperature? I mean if reference sea level temperature keeps the same when WRF deals with different data set?
 
Second, for two different data sets, if WRF keeps sea level temperature the same , and at the same time, top of pressure and the vertical layers are set to be the same, Does that mean the reference potential temperature for each vertical levels are the same for the two data set, and when I want to compare predicted temperature, I can directly compare the perturbation potential temperature?

Third, If I can not directly compare the  perturbation potential temperature to see the difference of predicted temperature, is there any way that I can convert the perturbation potential temperature to absolute temperature?

Thank you very much.

Peng