[ncl-talk] Interpolation error

[Sunmin Park]

Dear NCL users,

I have a problem to do interpolation using NorESM1 model results. I am using extinction coefficient values and when I read the data from the files, the MIN and MAX values are 
"(0)	Ambient Aerosol Extinction at 550 nm: min=0   max=0.00242234 “
But after interpolation the values are
"(0)	min=-2.58212e+22   max=0.0127834”

I do not understand why the values are changing and the MIN value shows minus. How can I fix it?

Thank you for any help!!

Sun-

; ==============================================================
; Open the file:
; ==============================================================
  fili    = "ec550aer_aero_NorESM1-M_historicalExt_r1i1p1_200601-201212.nc"
;  fili    = "ec550aer_aero_NorESM1-M_historicalExt_"+version(ii)+"i1p1_200601-201212.nc"
  varname = "ec550aer"
  varname1 = "a"
  varname2 = "b"
  varname3 = "ps"
  varname4 = "p0"
  filenc       = addfile (diri+fili+".nc", "r")      ; entire file
;  printMinMax(varname,0)
;  print(varname1)
;  print(varname2)
;  print(varname3)
;  print(varname4)
;  print (filenc)
;  return

  data   = filenc->$varname$                          ; (time, ver, lat, lon)
;  print (dimsizes(data))
  time =filenc->time
  lev =filenc->lev
  lat =filenc->lat
  printMinMax(data,0)
  printVarSummary(data)
;return
  lon =filenc->lon
;  print(time)
;  print(lev)
;  print(lat)
;  print(lon) 
;  data at _FillValue=1e+20
;  newlev =lev*1000
;  print(newlev)

;return

;############Converting from hybrid levels to standard pressure levels######################################
hyam = filenc->a
hybm = filenc->b
plev0 = (/1000,925,850,700,600,500,400,300,250,200,150,100,70,50,30,20,10/)
psfc = filenc->ps
p0=1000.

;printVarSummary(psfc)
;printVarSummary(hyam)

ec550aer = data;filenc->ec550aer                ; read ec550aer from all files
ec550aerNEW=vinth2p(ec550aer,hyam,hybm,plev0,psfc,1,p0,1,True)
delete(ec550aer)
ec550aer=ec550aerNEW
delete(ec550aerNEW)
printVarSummary(ec550aer)
printMinMax(ec550aer,0)
return
;###################################################################################


RESULTS

(0)	Ambient Aerosol Extinction at 550 nm: min=0   max=0.00242234

Variable: data
Type: float
Total Size: 120766464 bytes
            30191616 values
Number of Dimensions: 4
Dimensions and sizes:	[time | 84] x [lev | 26] x [lat | 96] x [lon | 144]
Coordinates:
            time: [15.5..2539.5]
            lev: [0.9925560999999998..0.00354463800000001]
            lat: [ -90..  90]
            lon: [   0..357.5]
Number Of Attributes: 12
  standard_name :	volume_extinction_coefficient_in_air_due_to_ambient_aerosol
  long_name :	Ambient Aerosol Extinction at 550 nm
  comment :	"""ambient"" means ""wetted"".  "
  units :	m-1
  original_name :	BAK
  original_units :	1/km


Variable: ec550aer
Type: float
Total Size: 78962688 bytes
            19740672 values
Number of Dimensions: 4
Dimensions and sizes:	[time | 84] x [lev_p | 17] x [lat | 96] x [lon | 144]
Coordinates:
            time: [15.5..2539.5]
            lev_p: [1000..10]
            lat: [ -90..  90]
            lon: [   0..357.5]
Number Of Attributes: 1
  _FillValue :	1e+20
(0)	min=-2.58212e+22   max=0.0127834