;+
;
; .. _ws_correction_ncdf.pro:
;
; ======================
; ws_correction_ncdf.pro
; ======================
;
; Correction of ws on OAFLUX grid
;
; :file:`${PROJECT_OD}/erai_ws_19890101_20091231_oafluxgrid.nc` have been
; produced by :ref:`interp_erai_ws_1989_2009.pro`.
;
; Corrected ws on OAFLUX grid is written in
; :file:`${PROJECT_OD}/TropFlux_ws_19890101_20091231.nc`
; if this file not already exists.
;
; This file will be used by :ref:`TropFlux_19890101_20091231.pro`.
;
;     .. graphviz::
;
;        digraph ws_correction_ncdf {
;           graph [
;           rankdir="LR",
;           ]
;
;           file_in [shape=ellipse,fontname=Courier,label="${PROJECT_OD}/erai_ws_19890101_20091231_oafluxgrid.nc"];
;           file_out [shape=ellipse,fontname=Courier,label="${PROJECT_OD}/TropFlux_ws_19890101_20091231.nc"];
;
;           ws_correction_ncdf [shape=box,
;           fontname=Courier,
;           color=blue,
;           URL="http://forge.ipsl.jussieu.fr/tropflux/browser/trunk/src/ws_correction_ncdf.pro",
;           label="${PROJECT}/src/ws_correction_ncdf.pro"];
;
;           {file_in} -> {ws_correction_ncdf} -> {file_out}
;
;          }
;
; SEE ALSO
; ========
;
; :ref:`project_profile.sh`
;
; :ref:`mooring_corrections`
;
; :ref:`interp_erai_vs_1989_2009.pro`
;
; :func:`initncdf <saxo:initncdf>`
; :func:`read_ncdf <saxo:read_ncdf>`
; :func:`grossemoyenne <saxo:grossemoyenne>`
; :func:`julday <saxo:julday>`
; :func:`caldat <saxo:caldat>`
; :func:`ncdf_quickwrite <saxo:ncdf_quickwrite>`
;
; EXAMPLES
; ========
;
; ::
;
;  IDL> ws_correction_ncdf
;
; TODO
; ====
;
; coding rules
;
; hard coded correction
;
; KNOWN ISSUES
; ============
;
; test of existence of fullfilename_in not very efficient because
; MUST_EXIST keyword of :func:`isafile <saxo:isafile>` not yet implemented
;
; EVOLUTIONS
; ==========
;
; - fplod 20110808T131954Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * usage of ${PROJECT_OD}
;   * complete description
;   * remove v20 in output filename

; - fplod 20101215T115916Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * add graph in header
;
; - fplod 20101214T093615Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * minimal header
;
; - pbk 2008
;
;   * creation
;
;-
pro ws_correction_ncdf
;
@cm_4cal
@cm_4data
@cm_4mesh
@cm_4data
@cm_project
;
; test if ${PROJECT_OD} defined
CASE project_od_env OF
  '' : BEGIN
         msg = 'eee : ${PROJECT_OD} is not defined'
         ras = report(msg)
       STOP
       END
  ELSE: BEGIN
          msg = 'iii : ${PROJECT_OD} is ' + project_od_env
          ras = report(msg)
        END
 ENDCASE
;
; check if output data will be possible
iodirout = isadirectory(project_od_env)
;
; existence and protection for reading
IF (FILE_TEST(iodirout, /DIRECTORY, /EXECUTABLE, /READ) EQ 0) THEN BEGIN
   msg = 'eee : the directory' + iodirout  + ' is not accessible.'
   ras = report(msg)
   STOP
ENDIF
;
; existence and protection for writing
IF (FILE_TEST(iodirout, /DIRECTORY, /WRITE) EQ 0) THEN BEGIN
    msg = 'eee : the directory' + iodirout  + ' was not found.'
    ras = report(msg)
    STOP
ENDIF
;
da1=19880101 & da2=20101231
;
; build data filename
filename='erai_ws_19890101_20091231_oafluxgrid.nc'
;
; check if this file exists
fullfilename = isafile(iodirout + filename, NEW=0, /MUST_EXIST)
IF fullfilename[0] EQ '' THEN BEGIN
   msg = 'eee : the file ' + fullfilename + ' was not found.'
   ras = report(msg)
   STOP
ENDIF
;
; build output filename
filename_out = 'TropFlux_ws_19890101_20091231.nc'
fullfilename_out = iodirout + filename_out
; in order to avoid unexpected overwritten
IF (FILE_TEST(fullfilename_out) EQ 1) THEN BEGIN
   msg = 'eee : the file ' + fullfilename_out  + ' already exists.'
   ras = report(msg)
   STOP
ENDIF
;
initncdf, fullfilename
u=read_ncdf('u10',da1,da2,file=fullfilename,/nostr)
v=read_ncdf('v10',da1,da2,file=fullfilename,/nostr)
w=sqrt(u*u+v*v)

help, w

w_mean=grossemoyenne(w,'t',/nan)
help, w_mean

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

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

w_ano=w-w_m

;; correction for mean based on scatter
;w_m=w_m+0.282667    ;; (2000-2008)
w_m=w_m+0.276739     ;; (2000-2009)

help, w_ano

;; applying the correction for varyability based on the scatter
;w_ano=w_ano*(1/0.897667)   ;; (2000-2008)
w_ano=w_ano*(1/0.903587)    ;; (2000-2009)

w_new=w_m+w_ano
help, w_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='!' + fullfilename_out
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'}
w_attr={units:'m/s',missing_value:1.e20,long_name:'mean wind speed',short_name:'w',axis:'TYX'}
globattr={source:'Basic data obtained from ERAI. Bias and variability correction are applied',timerange:cda0+' - '+cda1}

ncfields = 'ws[longitude,latitude,time]=w_new:w_attr; ' $
                      + 'longitude[]=lon:lon_attr; ' $
                      + 'latitude[]=lat:lat_attr; ' $
                      + 'time[*time]=time:time_attr ' $
                      + ' @ globattr'

@ncdf_quickwrite

end