Re: pt&ept

Dear Respected Dr.Dennis Shea,

Thanks for your help. I am interesting to plot the figure Press/height vs.
latitude (like the ncl example (h_lat_2.ncl). My code is attached
herewith, I'm confused about the function used in the code. Thanks advance
for your help.

 regrads,

 load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

 load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"

 load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"

 function theta_eqv(T:numeric, X:numeric, p0[1], p[*]:numeric)

 local T_e, L_v, c_pd, R, Rcpd, dimT, dimX, P

  begin

   L_v = 2400. ; Latent heat of evaporation [approx 2400 kJ/kg at 25C]

   c_pd = 1004. ; Specific heat at constant pressure for air [approx 1004
J/(kg-K)]

   R = 287. ; Specific gas constant for air [J/(kg-K)]

   Rcpd = R/c_pd

   dimT = dimsizes(T)

   dimX = dimsizes(X)

   if (dimsizes(dimT) .ne. dimsizes(dimX)) then

   print("theta_eqv: rank of T .ne. rank of X")

   exit

   end if

   P = conform(T,p,1) ; make p same shape/rank/size as T

   T_e = "/T+(L_v/c_pd)*X/" ; common approximation

   theta_e = "/T_e*(p0/P)^Rcpd/"

   theta_e@long_name = "Equivalent potential temperature"

   theta_e@units = "K"

   ;copy_VarCoords(T, theta_e) ; assign coordinates

   return(theta_e)

   end

  begin

   diri = "/data/ncep_data/pressure/"

   f = addfile(diri+"air.2001.nc", "r")

   a = short2flt(f->air(0:29,:,:,:))

   f1 = addfile(diri+"shum.2001.nc","r")

   sh = short2flt(f1->shum(0:29,:,:,:))

   aavg = dim_avg_Wrap(a(level|:,lat|:,lon|:,time|:))

   shavg = dim_avg_Wrap(sh(level|:,lat|:,lon|:,time|:))

   printVarSummary(shavg)

   p = f->level

   T = f->air

   x = f1->shum ; spc humidity

   X = x/(1-x) ; convert spc humidity to mixing ratio

   X@long_name = "mixing ratio"

   p0 = 1000

   p0@units = "hPa" ; must match units of p

   THETAE = theta_eqv(T, X, p0, p)

   printVarSummary( THETAE )

 ; printMinMax(THETAE, True )

   lat = f->lat

   lev_p = 100*(f->level)

   lev_p@units = "Pa"

  THETAE =
zonal_mpsi(aavg(::-1,:,{30:70}),aavg&lat,lev_p(::-1),shavg(:,{30:70}))

   THETAE!0 = "lev"

   THETAE!1 = "lat"

   THETAE&lev = lev_p

   THETAE&lat = lat

   THETAE@long_name = "ept"

   wks = gsn_open_wks ("x11", "pot" )

   plot = gsn_csm_pres_hgt(wks,THETAE(:,{10:20}), False )

   end

Variable: THETAE

Type: string

Total Size: 4 bytes

            1 values

Number of Dimensions: 1

Dimensions and sizes: [1]

Coordinates:

Number Of Attributes: 2

  long_name : Equivalent potential temperature

  units : K

fatal:Number of subscripts do not match number of dimensions of variable,(2)
Subscripts used, (3) Subscripts expected

fatal:Execute: Error occurred at or near line 56 in file pot1.ncl

On Wed, May 26, 2010 at 11:15 PM, Dennis Shea <shea@ucar.edu> wrote:

> This question is ambiguous. Please be specific.
>
> [1] Do you mean a plot over a map at a specific level?
>
> See Example 2 at: http://www.ncl.ucar.edu/Applications/iso.shtml
>
> This also includes an example of calculating potential temperature
> and equivalent potential temperature.
>
> [2] Do you mean pres/height vs lat or lon or time or ?
>
>
> http://www.ncl.ucar.edu/Applications/
>
> Click:
> Press/height vs. latitude
> Press/height vs. longitude
> Press/height vs. time
>
> =============
>
>
>
>
> On 5/25/10 7:57 PM, wei huang wrote:
>
>> Dear All,
>> Does anyone could share me a script or guided me for plotting the
>> potential temperature at a height level (from surface to 200mb) and also
>> equivalent potential temperature? Your help will be appreciated.
>>
>> Thanks in advance
>>
>> Wei
>>
>>
>>
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>

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Received on Wed May 26 11:39:58 2010