;+
;
; .. _t2m_correction_ncdf.pro:
;
; =======================
; t2m_correction_ncdf.pro
; =======================
;
; SEE ALSO
; ========
;
; EXAMPLES
; ========
;
; ::
;
;  IDL> t2m_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 t2m_correction_ncdf
@common
da1=19890101 & da2=20091231

file='/Volumes/Iomega_HDD/TropFlux/input_uncor/erai_t2m_19890101_20091231_oafluxgrid.nc'
initncdf, file
t2m=read_ncdf('t2m',da1,da2,file=file,/nostr) & t2m=t2m-273.15
help, t2m

t2m_mean=grossemoyenne(t2m,'t',/nan)
help, w_mean

tt=time & jpt=n_elements(time)
caldat, time,mon,day,yea
t2m_m=t2m*0.
bias_cor=t2m*0.

;; line fit ->  -0.0755589x + 1.71090   ;; (2000-2008)
;; line fit ->  -0.0741607x + 1.67601   ;; (2000-2009)

for jt=0,jpt-1 do begin
  jtt=(time(jt)-julday(1,1,yea(jt))) < 364
  t=reform(t2m_mean(*,*))
  t2m_m(*,*,jt)=t
  bias_cor(*,*,jt)=(((t-22.6)*0.4004896/(28-22.6)) > 0.) <0.4     ;; (2000-2009)
endfor
help, t2m_m,bias_cor

t2m_ano=t2m-t2m_m

;; correction for mean based on scatter

help, t2m_ano

;; applying the correction for varyability based on the scatter
;t2m_ano=t2m_ano*(1/0.916484)    ;; (2000-2008)
t2m_ano=t2m_ano*(1/0.918085)     ;; (2000-2009)

;; applying the correction for varyability based on the scatter
t2m_m=t2m_m+bias_cor

t2m_new=t2m_m+t2m_ano+273.15
help, t2m_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)) & 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/Iomega_HDD/TropFlux/input_cor/full_cor/TropFlux_t2m_19890101_20091231_v20.nc'
ncfile='!/Users/pkb/data/TropFlux/TropFlux_t2m_19890101_20091231_v50.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'}
t2m_attr={units:'degK',missing_value:1.e20,long_name:'Air Temperature at 2m',short_name:'t2m',axis:'TYX'}
globattr={source:'Basic data obtained from ERAI.  Mean correction for air temperautre bias and correction for variability are applied',timerange:cda0+' - '+cda1}


ncfields = 't2m[longitude,latitude,time]=t2m_new:t2m_attr; ' $
                      + 'longitude[]=lon:lon_attr; ' $
                      + 'latitude[]=lat:lat_attr; ' $
                      + 'time[*time]=time:time_attr ' $
                      + ' @ globattr'

@ncdf_quickwrite

end