function read_arr2d, filename, varname, t1, t2
;; function that read input file and return 2d array with monthly timecounter 
nyear = (t2-t1+1)/12
arr2d = ncdf_lec(filename, VAR=varname)
arr2d = arr2d[t1:t2]
arr2d = reform(arr2d,12,nyear) ; put in 2D array
arr2d = total(arr2d,2)/nyear ; total over 2th dimension (i.e.years)

return, arr2d
end 

;
;
pro std_ts_SNOW_Vol, masknp, s_iodir_data,  POSTSCRIPT = postscript, _extra = ex

  compile_opt idl2, strictarrsubs
  
@common
@std_common

; get exp1 info
  vICE1     = getenv('VAR1_SNOW')     &   prefix = getenv('V1SNOW_PREF')  &   suffix = getenv('V1SNOW_SUFF')

;;;;SF ???? come faccio lo snow volume se ho solo snowthickness???
;;;;SF ???? quale variabile in output nel file iodef? e moltiplicarla per snowthicness?



  v1_Ithick = getenv('VAR1_Ithick')  &   prefix = getenv('V1It_PREF')   &   suffix = getenv('V1It_SUFF')
; get exp2 info
  vICE2     = getenv('VAR2_ICE')     &   prefix2 = getenv('V2ICE_PREF')   &   suffix2 = getenv('V2ICE_SUFF')
  v2_Ithick = getenv('VAR2_Ithick')  &   prefix2 = getenv('V2It_PREF')    &   suffix2 = getenv('V2It_SUFF')

; get ice climatology info
;
;; METTERE CLIMATOLOGIA VOLUME SE TROVATA
;
;  std_file_ice =  isafile(getenv('FILE_ICE'), title = 'ICE Extent Climatology', iodir = std_iodir_climato)
;
;  time_ice = ncdf_lec( std_file_ice, VAR='time' )
;  time_ice = (time_ice - FLOOR(time_ice) ) * 12
;  time_ice = round(time_ice) ; round to nearest integer 
;  t1 = where(time_ice eq 0)
;  t1 = t1[0] ;  jannuary
;  t2 = where(time_ice eq 11, count)
;  t2 = t2[count-1] ; last day of december
;  nyear = (t2-t1+1)/12
;  vICE_Ithick_NH = read_arr2d(std_file_ice, getenv('VAR1_Ithick'), t1, t2 )
;  vICE_Ithick_SH = read_arr2d(std_file_ice, getenv('VAR_ICE_EXT_SH'), t1, t2 )
;
; vICE_area_NH = read_arr2d(std_file_ice, getenv('VAR_ICE_area_NH'), t1, t2 )
;  vICE_area_SH = read_arr2d(std_file_ice, getenv('VAR_ICE_area_SH'), t1, t2 )
;  
  cdti3 = string(cnt, format = '(i3.3)')
  print, cdti3 + ') ' + blabla
  filename = cdti3 + '_ts_ICE_'+prefix
  if prefix NE prefix2 then filename = filename + '_'+prefix2
  if KEYWORD_SET(postscript) then openps, filename+'.ps', portrait = 1
  d1_d2 = '('+strtrim(date1, 1)+' - '+strtrim(date2, 1)+')'
  iodir = std_iodir_data
  ; ICE Area(=Surface) in NORTH Hemisphere
  domdef, 0, jpi-1, 30, 90, /xindex
  ICE_N = rseries_ncdf(vICE1, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
  ICE_thick = rseries_ncdf(v1_Ithick, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
  ; Volume = Area(=Surface) * Thickness
  ICE_vol_N = (ICE_N.arr < 1.e10 ) * ( ICE_thick.arr < 1.e10)  ; limited mask value of 1.e20, because 1.e20 * 1.e20 = inf for idl
  ICE_vol_N = grossemoyenne(ICE_vol_N, 'xy', /integration, mask2d = masknp)
  if jpt mod 12 ne 0 then stop
  nyr=jpt/12.
  ICE_vol_N = reform(ICE_vol_N, 12, nyr)
  ICE_vol_N = total(ICE_vol_N,2)/nyr
 ; ICE_vol_N = {arr:ICE_vol_N * 1.e-3, unit : '10^3 Km^3'}
  ICE_vol_N = {arr:ICE_vol_N * 1.e-9, unit : '10^9 Km^3'}
  ;ICE Area(=Surface) in SOUTH Hemisphere
  domdef, 0, jpi-1, -90, -30, /xindex 
  ICE_S = rseries_ncdf(vICE1, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
  ICE_thick = rseries_ncdf(v1_Ithick, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
  ; Volume = Area(=Surface) * Thickness
  ICE_vol_S = (ICE_S.arr < 1.e10 ) * ( ICE_thick.arr < 1.e10)  ; limited mask value of 1.e20, because 1.e20 * 1.e20 = inf for idl
  ICE_vol_S = grossemoyenne(ICE_vol_S, 'xy', /integration, mask2d = masknp)
  if jpt mod 12 ne 0 then stop
  nyr=jpt/12.
  ICE_vol_S = reform(ICE_vol_S, 12, nyr)
  ICE_vol_S = total(ICE_vol_S,2)/nyr
;print, 'prima valore di ice vol s'
;print, ICE_vol_S
  ICE_vol_S = {arr:ICE_vol_S * 1.e-9, unit : '10^9 Km^3'}
;print, 'DOPO valore di ice vol s'
;print, ICE_vol_S
  ;
  title = 'Northern Hemisphere'+'!C'+prefix+' '+d1_d2+'!C'+'Global Annual Mean Ice Volume (Black SOLID simulation) + Observation (dashed)'
  jpt=12
  time=julday(1,15,1900)+30*lindgen(12)
  pltt, ICE_vol_N, 't', 0., 15., 19000101, 19001231, /REMPLI, /PORTRAIT,MIN = 0., MAX = 30000. $
        , small = [1, 2, 1], YTITLE = '10^9 Km^3 ', TITLE = title, _extra = ex
;
  title ='Southern Hemisphere' +'!C'+prefix+' '+d1_d2+' - '+'!C'+'Global Annual Mean Ice Volume (Black SOLID simulation) + Observation (dashed)'
  pltt, ICE_vol_S, 't', 0., 15.,19000101 ,19001231 , /REMPLI, /NOERASE , MIN = 0., MAX = 11000. $
        , small = [1, 2, 2], YTITLE = '10^9 Km^3 ', TITLE = title, _extra = ex
;

;;return
  htmltxt = [ htmltxt, '<hr>'+blabla, '<br><img width="80%" src='+filename+'.png  />  ' ]
  if KEYWORD_SET(postscript) then closeps

  if prefix NE prefix2 then BEGIN

    d1_d2_2 = '('+strtrim(date1_2, 1)+' - '+strtrim(date2_2, 1)+')'
    tsave = time
    domdef, 0, jpi-1, 30, 90, /xindex
    ;ICE Extent in NORTH Hemisphere
    ICE_N2 = rseries_ncdf(vICE2, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
    ICE_thick2 = rseries_ncdf(v2_Ithick, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
    ; Volume = Area(=Surface) * Thickness
    ICE_vol_N2 = (ICE_N2.arr < 1.e10 ) * ( ICE_thick2.arr < 1.e10) ; limited mask value of 1.e20, because 1.e20 * 1.e20 = inf for idl
    ICE_vol_N2 = grossemoyenne(ICE_vol_N2, 'xy', /integration, mask2d = masknp)
    if jpt mod 12 ne 0 then stop
    nyr=jpt/12.
    ICE_vol_N2 = reform(ICE_vol_N2, 12, nyr)
    ICE_vol_N2 = total(ICE_vol_N2,2)/nyr
    ICE_vol_N2 = {arr:ICE_vol_N2 * 1.e-9, unit : '10^3 Km^3'}

    ;ICE Area(=Surface) in SOUTH Hemisphere
    domdef, 0, jpi-1, -90, -30, /xindex 
    ICE_S2 = rseries_ncdf(vICE2, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
    ICE_thick2 = rseries_ncdf(v2_Ithick, date1, date2, prefix, suffix, FIRSTONLY = 1 - allrec)
    ; Volume = Area(=Surface) * Thickness
    ICE_vol_S2 = (ICE_S2.arr < 1.e10 ) * ( ICE_thick.arr < 1.e10) ; limited mask value of 1.e20, because 1.e20 * 1.e20 = inf for idl
    ICE_vol_S2 = grossemoyenne(ICE_vol_S2, 'xy', /integration, mask2d = masknp)
    if jpt mod 12 ne 0 then stop
    nyr=jpt/12.
    ICE_vol_S2 = reform(ICE_vol_S2, 12, nyr)
    ICE_vol_S2 = total(ICE_vol_S2,2)/nyr
    ICE_vol_S2 = {arr:ICE_vol_S2 * 1.e-9, unit : '10^3 Km^3'}

    time = tsave   &   IF n_elements(time) NE jpt THEN stop

    if KEYWORD_SET(postscript) then openps, filename+'.ps', portrait = 1

    title = prefix+' '+d1_d2+' - '+prefix2+' '+d1_d2_2+'!C'+'Global Annual Mean Ice Volume (North. Hemisp.)'
    pltt, ICE_vol_N.arr - ICE_vol_N2.arr, 't', -2., 2., date1, date2, /REMPLI, /PORTRAIT, window = 2 $
          , COLOR = 250, small = [1, 2, 1], YTITLE = '10^9 Km^3 ', TITLE = title, _extra = ex
   ;
    title = prefix+' '+d1_d2+' - '+prefix2+' '+d1_d2_2+'!C'+'Global Annual Mean Ice Area (South. Hemisp.)'
    pltt, ICE_vol_S.arr - ICE_vol_S2.arr, 't', -2., 2., date1, date2, /REMPLI, /NOERASE $
          , COLOR = 250, small = [1, 2, 2], YTITLE = '10^9 Km^3 ', TITLE = title, _extra = ex    

    htmltxt = [ htmltxt, '<hr>'+blabla, '<br><img width="80%" src='+filename+'.png  />  ' ]
    if KEYWORD_SET(postscript) then closeps

  endif

  domdef

  return
end