;+
;
; .. _q2m_correction_ncdf.pro:
;
; =======================
; q2m_correction_ncdf.pro
; =======================
;
; SEE ALSO
; ========
;
; EXAMPLES
; ========
;
; ::
;
;  IDL> q2m_correction_ncdf
;
; TODO
; ====
;
; hard coded directory - usage of ${TROPFLUX_ID}
;
; coding rules
;
; EVOLUTIONS
; ==========
;
; - fplod 20101214T093615Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * minimal header
;
; - pbk 2008
;
;   * creation
;
;-
pro q2m_correction_ncdf
@common
;----------------------------------------------------------------------
da1=19880101 & da2=20101231

file='/Volumes/PRAVEEN/TropFlux/input_uncor/erai_q2m_19890101_20091231_oafluxgrid.nc'
initncdf, file
q2m=read_ncdf('q2m',da1,da2,file=file,/nostr)
help, q2m

q2m_mean=grossemoyenne(q2m,'t',/nan)
help, q2m_mean
;----------------------------------------------------------------------

tt=time & jpt=n_elements(time)
caldat, time,mon,day,yea
q2m_m=q2m*0.

for jt=0,jpt-1 do begin
  jtt=(time(jt)-julday(1,1,yea(jt))) < 364
  q=reform(q2m_mean(*,*))
  q2m_m(*,*,jt)=q
endfor
help, q2m_m

q2m_ano=q2m-q2m_m

;; correction for mean based on scatter
;q2m_m=q2m_m+0.815445  ;;  (2000-2008)
q2m_m=q2m_m+0.792717   ;;  (2000-2009)
help, q2m_ano

;; applying the correction for varyability based on the scatter
;q2m_ano=q2m_ano*(1/0.919333)  ;;  (2000-2008)
q2m_ano=q2m_ano*(1/0.924674)   ;;  (2000-2009)

q2m_new=q2m_m+q2m_ano
help, q2m_new

;----------------------------------------------------------------------
;writing field
lat=reform(gphit(0,0:jpj-1))
lon=reform(glamt(0:jpi-1,0))
time=timegen(7670, units='days', start=julday(1,1,1989,0)) & jpt=n_elements(time)

cda0=string(jul2date(time(0)),format='(i8.8)')
cda1=string(jul2date(time(jpt-1)),format='(i8.8)')

time=time-julday(1,1,1950) & jpt=n_elements(time)

ncfile='!/Volumes/PRAVEEN/TropFlux/input_cor/full_cor/TropFlux_q2m_19890101_20091231_v20.nc'
lon_attr={units:'degrees_east',long_name:'Longitude'}
lat_attr={units:'degrees_north',long_name:'Latitude'}
time_attr={units:'days since 1950-01-01 00:00:00',long_name:'Time axis',time_origin:'1950-JAN-01 00:00:00'}
q2m_attr={units:'g/kg',missing_value:1.e20,long_name:'Specific humidity at 2m height',short_name:'q2m',axis:'TYX'}
globattr={source:'Basic data obtained from ERAI.  Mean correction for bias and correction for variability are applied',timerange:cda0+' - '+cda1}


ncfields = 'q2m[longitude,latitude,time]=q2m_new:q2m_attr; ' $
                      + 'longitude[]=lon:lon_attr; ' $
                      + 'latitude[]=lat:lat_attr; ' $
                      + 'time[*time]=time:time_attr ' $
                      + ' @ globattr'

@ncdf_quickwrite

end