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

[Mary Haley]

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).

Thanks,

--Mary


On Fri, May 27, 2016 at 1:33 PM, Agud Pique, Enric <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"
> begin
> 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
> ;-----------------------------------------
>
>
> undef("calc_thetae")
>
> 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
>
> begin
> 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]
> return(thetae)
> end
>
> contour_t2 = wrf_contour(a,wks,thetae,opts)
>
> plot= wrf_map_overlays(a,wks,(/contour_t2/),pltres ,mpres)
>
> end
>
> Best
>
>
>
> Enric
>
> *De:* Agud Pique, Enric
> *Enviat:* dimarts, 24 / maig / 2016 21:17
> *Per a:* 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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