f = addfile("ppt.nc","r")
  
  yrStrt = 195001               ; Data inicial => AAAAMM
  yrLast = 195112               ; Data final   => AAAAMM
  
  TIME   = f->time              ; Importação da variável time do arquivo f.
  YYYY   = cd_calendar(TIME,-1) ; Tempo no formato AAAAMM (opção -1).
  
  ti = ind(YYYY.eq.yrStrt)
  tf = ind(YYYY.eq.yrLast)
  
  print("")
  print("Periodo selecionado :" + YYYY(ti) +"-"+ YYYY(tf))
  print("")
  
  ppt         = f->pr(ti:tf,:,:)
  printVarSummary(ppt)                        ; [time | 24] x [lat | 145] x [lon | 192]
  print(ppt&time)
  
  ppt_anual   = month_to_annual(ppt,0)         
  printVarSummary(ppt_anual)                  ; [year | 2] x [lat | 145] x [lon | 192]
  
  ppt_anual!0 = "time"                        ; rename the dimension
  printVarSummary(ppt_anual)

  ppt_anual&time = ppt&time(::12)             ; pick every 12-th value  (January)
  printVarSummary(ppt_anual)
  print(ppt_anual&time)                       ; units => days since 1859-12-1 00:00:00
                                              ; calendar :    360_day
  ymdh = cd_calendar(ppt_anual&time, -3)      ; center-of-mass(time) for January
  print(ymdh)                                 ; (/ 1950011600, 1950011600 /)

; subtract 15 days to get beginning of month 

  ppt_anual&time = (/ ppt_anual&time - 15 /)
  YMDH = cd_calendar(ppt_anual&time, -3)      ; center-of-mass(time) for January
  print(YMDH)                                 ; (/ 1950010100, 1950010100 /)
  printVarSummary(ppt_anual&time)             ; 

  ppt_anual&time = cd_convert( ppt_anual&time, "seconds since 1900-01-01 00:00" )
  print(ppt_anual&time)                       ; calendar attribute changes: 360_day ==> standard
  ymdh_sec = cd_calendar(ppt_anual&time, -3)  ;  January 1
  print(ymdh_sec)                             ; (/ 1950010100, 1950010100 /)
exit

  printVarSummary(ppt_anual)
  
  ppt_anual = lonFlip(ppt_anual)
  ppti = g2fsh_Wrap(ppt_anual,(/73,144/)) ; Interpola o dado.
  printVarSummary(ppti)  ; [time | 2] x [lat | 73] x [lon | 144]
  
  system("/bin/rm -f tmp.nc")
  nc    = addfile("tmp.nc","c")
  nc->p = ppti