[ncl-talk] calculate a variable from other wrf variables and plot it

Agud Pique, Enric eagud.q at ccma.cat
Sat May 28 01:25:46 MDT 2016

Hello Mary,

I get this error

[Enric at meteo em_real]$ ncl plot2.ncl
 Copyright (C) 1995-2015 - All Rights Reserved
 University Corporation for Atmospheric Research
 NCAR Command Language Version 6.3.0
 The use of this software is governed by a License Agreement.
 See http://www.ncl.ucar.edu/ for more details.
fatal:syntax error: line 15 in file plot2.ncl before or near =
relhum =

fatal:error in statement
fatal:Syntax Error in block, block not executed
fatal:error at line 66 in file plot2.ncl

De: Mary Haley [haley at ucar.edu]
Enviat el: dissabte, 28 / maig / 2016 00:03
Per a: Agud Pique, Enric
A/c: ncl-talk at ucar.edu
Tema: Re: [ncl-talk] calculate a variable from other wrf variables and plot it

Does running the script produce an error message? If so, please email the exact error message.

I do see that you are imbedding a function inside the main code. I believe this is acceptable in NCL, but just to be sure, I need to see what your error message states.

If there's no error message, then describe in more detail what the problem is (i.e. if the plot is bad, describe how it is bad, and include an image if possible).



On Fri, May 27, 2016 at 1:33 PM, Agud Pique, Enric <eagud.q at ccma.cat<mailto:eagud.q at ccma.cat>> wrote:
Hello people,

I would like to plot a variable calculated from several wrf variables....for example, the following code....get temperature, pressure and relative humidity and after I select tempC and relhum in 850 hPa... after calculate Theta E, I want to plot it, but when I execute the scripts it fails...what is wrong?

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
a = addfile("./wrfout_d01_2016-05-24_18:00:00","r")
wks = gsn_open_wks("X11","plt_Surface")

tc = wrf_user_getvar(a,"tc",0)
p = wrf_user_getvar(a,"pressure",0)
rh = wrf_user_getvar(a,"rh",0)
pressure = 850.
res = True

tempC = wrf_user_intrp3d(tc,p,"h",850.,0.,res)
relhum= wrf_user_intrp3d(rh,p,"h",850.,0.,res)

pltres = True
mpres = True

opts = res
opts at cnFillOn = True
opts at cnLevelSelectionMode = "ExplicitLevels"

; Calculate Theta E


function calc_thetae(tempC,pres,relhum)

local tempC, pres, relhum, tc, tk, pp, p0, rh, es, en, rv, rd, cp, kd, td, tl, thetal, thetae

pres = 850.
Tc = tempC                                                          ; [C]
tk = tempC+273.15                                                   ; [K]
pp = pres                        ; [hPa]
p0 = 1000                                        ; [hPa]
rh = relhum/100                          ; [no dimensions]
es = 6.112*exp(17.67*Tc/(Tc+243.5))                  ; [hPa]
en = rh*es                                       ; [hPa]
rv = 0.622*en/(pp-en)                  ; [no dimensions]
rd = 287.04                          ; [J/kgK]
cp = 1005.7                                    ; [J/kgK]
kd = rd/cp                                 ; [no dimensions]
tl = (1/((1/(tk-55))-(log(rh)/2840)))+55                 ; [K]
thetal = tk*((p0/(pp-en))^kd)*((tk/tl)^(0.28*rv))        ; [K]
thetae = thetal*exp(((3036/tl)-1.78)*rv*(1+0.448*rv))    ; [K]
thetae = thetae-273.15                                              ; [C]

contour_t2 = wrf_contour(a,wks,thetae,opts)

plot= wrf_map_overlays(a,wks,(/contour_t2/),pltres ,mpres)



De: Agud Pique, Enric
Enviat: dimarts, 24 / maig / 2016 21:17
Per a: ncl-talk at ucar.edu<mailto:ncl-talk at ucar.edu>
Tema: get some variables from wrf output

Hello people,

I would like to use wrf_user_getvar or another function in order to get from a wrf filet he following variables:

Temperature on 850 hPa-Level in ºC,
Geopotential height on 850 hPa-Level
Relative humidity on 850 hPa-Level

I know how to get the temperature on T2
T2 = wrf_user_getvar(a,"T2",0)
where a is the wrf file...but in 850hPa?

Thank you

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