NCL Home > Documentation > Functions > WRF


Calculates equivalent potential temperature from WRF model output.


	function wrf_eth (
		qv  : numeric,  
		T   : numeric,  
		P   : numeric   

	return_val [dimsizes(qv)] :  float or double



Water vapor mixing ratio in [kg/kg]. An array with the same dimensionality as P.


Temperature in [K]. An array with the same dimensionality as P. This variable can be calculated by wrf_tk.


Full pressure (perturbation + base state pressure). The rightmost dimensions are bottom_top x south_north x west_east. Units must be [Pa].

Return value

Equivalent potential temperature (K). An array of the same size as qv. The type will be double if any of the input is double, and float otherwise.


This function computes equivalent potential temperature (in K). The return variable will contain two attributes:

return_val@description = "Equivalent Potential Temperature"
return_val@units = "K"

Questions on this function should be sent to

See Also


See the full list of WRF functions.


Note: for WRF variable names and their definitions, you can easily check them by using "ncl_filedump":


Example 1

   nc_file = addfile("","r")
   T  = nc_file->T
   P  = nc_file->P
   PB = nc_file->PB
   qv = nc_file->QVAPOR
   T  = T + 300.        ; potential temperature in K.
   P  = P + PB          ; full pressure in Pa.   
   tk = wrf_tk( P , T ) ; temperature in K.

   eth = wrf_eth ( qv, tk, P )
You can see some other example scripts and their resultant images at: