;************************************************
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"   
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"    
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl
load "$HAO_NCL_LIB/halfzp2full.ncl"
load "$HAO_NCL_LIB/hao_contrib.ncl"
load "$HAO_NCL_LIB/axis.ncl"
;************************************************
begin
;************************************************
; before the data can be plotted, there is a 
; sequence of things that have to be done to it:
;************************************************
  in    = addfile("/chewy/d/murphys/files/pyrj001.nc","r")                
  x     = in->TN
  x     = halfzp("TN",x)                     ; convert to full zp

  t2plt   = 2                                ; time index to plot
  lat2plt = 56                               ; lat value to plot
;************************************************
; create plot
;************************************************
  wks = gsn_open_wks("ps" ,"zplon")           ; open a ps file
  gsn_define_colormap(wks,"gui_default")    

  res                          = True         ; plot mods desired
  res@cnLineLabelPlacementMode = "constant"   ; best line label mode
  res@cnFillOn                 = True         ; add color
  res@gsnSpreadColors          = True         ; use full range of color map
  res@cnLineLabelsOn           = True         ; contour line labels
  res@tiMainString             = "TN (degK) UT = "+in->ut(t2plt)+" Lat = "+lat2plt

; turn on local time axis. This function is located in axis.ncl
  res  = set_lt_axis_cnplot(in->ut(t2plt),False,res) 


; interpolate to height
  arg      = True
  arg@bott = 100          ; bottom height to start at
  arg@top  = 500          ; top height to end at
  arg@dz   = 10           ; height interval
  z        = in->Z        ; get Z
  x_int    = zplev_to_height(z,x,arg)

  plot = gsn_csm_contour(wks,x_int(t2plt,:,{lat2plt},:), res)


end