source: trunk/src/t2m_correction_ncdf.pro

;+
;
; =======================
; t2m_correction_ncdf.pro
; =======================
;
; .. function:: t2m_correction_ncdf(yyyymmddb,yyyymmdde)
;
; DESCRIPTION
; ===========
;
; Mean correction for air temperature bias and correction for variability are
; applied.
;
; :file:`${PROJECT_ID}/erai_t2m_{yyyymmdd}_{yyyymmdd}_oafluxgrid.nc`
; containing
; air temperature at 2 m height from ERA-I interpolated on OAFLUX grid
; has been produced by
; :func:`interp_erai_t2m`.
;
; Corrected air temperature at 2 m height
; is written in
; :file:`${PROJECT_OD}/TropFlux_t2m_{yyyymmdd}_{yyyymmdd}.nc`
; if this file not already exists.
;
; This output file
; :file:`${PROJECT_OD}/TropFlux_t2m_{yyyymmdd}_{yyyymmdd}.nc`
; will be used by
; :func:`tropflux`.
;
; .. only:: man
;
;    Figure is visible on PDF and HTML documents only.
;
; .. only:: html or latex
;
;     .. graphviz::
;
;        digraph t2m_correction_ncdf {
;
;           file_in [shape=ellipse,fontname=Courier,label="${PROJECT_OD}/erai_t2m_{yyyymmdd}_{yyyymmdd}_oafluxgrid.nc"];
;           file_out [shape=ellipse,fontname=Courier,label="${PROJECT_OD}/TropFlux_t2m_{yyyymmdd}_{yyyymmdd}.nc"];
;
;           t2m_correction_ncdf [shape=box,
;           fontname=Courier,
;           color=blue,
;           URL="http://forge.ipsl.jussieu.fr/tropflux/browser/trunk/src/t2m_correction_ncdf.pro",
;           label="${PROJECT}/src/t2m_correction_ncdf.pro"];
;
;           {file_in} -> {t2m_correction_ncdf} -> {file_out}
;
;        }
;
; SEE ALSO
; ========
;
; :ref:`mooring_corrections`
;
; Used by :ref:`tropflux.sh`
;
; :ref:`project_profile.sh`
;
; :func:`interp_erai_t2m`
;
; :func:`initncdf <saxo:initncdf>`
; :func:`read_ncdf <saxo:read_ncdf>`
; :func:`grossemoyenne <saxo:grossemoyenne>`
; :func:`caldat <saxo:caldat>`
; :func:`julday <saxo:julday>`
; :func:`jul2date <saxo:jul2date>`
; :func:`ncdf_quickwrite <saxo:ncdf_quickwrite>`
; :func:`ncdf_getatt <saxo:ncdf_getatt>`
;
; EXAMPLES
; ========
;
; .. code-block:: idl
;
;    yyyymmddb = 20000101L
;    yyyymmdde = 20001231L
;    result = t2m_correction_ncdf(yyyymmddb, yyyymmdde)
;    print, result
;
; TODO
; ====
;
; note .5 in time value ... is this correct ? do others files
; present the same feature ?
;
; .. code-block:: bash
;
;    ncks -v time -d time,0,1 /usr/work/incas/fplod/tropflux_d/TropFlux_t2m_19890101_20091231.nc
;
; .. parsed-literal::
;
;    time: type NC_DOUBLE, 1 dimension, 3 attributes, chunked? no, compressed? no, packed? no, ID = 3
;    time RAM size is 7670*sizeof(NC_DOUBLE) = 7670*8 = 61360 bytes
;    time dimension 0: time, size = 7670 NC_DOUBLE, dim. ID = 2 (CRD)(REC)
;    time attribute 0: units, size = 30 NC_CHAR, value = days since 1950-01-01 00:00:00
;    time attribute 1: long_name, size = 9 NC_CHAR, value = Time axis
;    time attribute 2: time_origin, size = 20 NC_CHAR, value = 1950-JAN-01 00:00:00
;
;    time[0]=14244.5 days since 1950-01-01 00:00:00
;    time[1]=14245.5 days since 1950-01-01 00:00:00
;
; coding rules
;
; understand usage of jtt
;
; check time values
;
; hard coded correction values
;
; check side effect of replacement of read_ncdf by ncdf_lec :
; Probleme d'adequation entre les tailles du domaine nx*ny*jpt 350*60*1 et du tableau 350*60*7670
;
; hard coded attributes
;
; CF conventions
;
; KNOWN ISSUES
; ============
;
; test of existence of fullfilename_msk not very efficient because
; MUST_EXIST keyword of :func:`isafile <saxo:isafile>` not yet implemented
;
; EVOLUTIONS
; ==========
;
; $Id: t2m_correction_ncdf.pro 88 2011-08-19 15:40:14Z pinsard $
;
; $URL$
;
; - fplod 20120322
;
;   * taking project_overwrite into account
;   * try to add compile_opt seems to be incompatible with ncdf_quickwrite
;   * pro -> function
;   * hard coded da1 and da2 replaced by yyyymmddb and yyyymmdde parameters
;   * replace t2m=ncdf_lec(... by a t2m=read_ncdf(
;
; - fplod 20110822T112525Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * correction for time values in output file
;
; - fplod 20110808T130628Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * remove v50 in filename output
;   * replace _ID by _OD (like other correction modules)
;
; - fplod 20110104T093758Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * complete header
;   * replace /Volumes/Iomega_HDD/TropFlux/input_uncor/ by ${TROPFLUX_ID}
;   * replace /Volumes/Iomega_HDD/TropFlux/input_cor/full_cor/ by
;     ${TROPFLUX_OD}
;   * use :func:`ncdf_getatt <saxo:ncdf_getatt>` for attributes of lat and long
;     variables
;   * same problem of time axis and memory like in interp_erai_t2m_1989_2009
;     using read_ncdf.
;     replace read_ncdf by netcdf_lec
;
; - fplod 20101215T114503Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * add graph in header
;
; - fplod 20101214T093615Z aedon.locean-ipsl.upmc.fr (Darwin)
;
;   * minimal header
;
; - pbk 2008
;
;   * creation
;
;-
function t2m_correction_ncdf $
, yyyymmddb $
, yyyymmdde
;
;++compile_opt idl2, strictarrsubs, logical_predicate
;
@cm_4cal
@cm_4data
@cm_4mesh
@cm_4data
@cm_project
;
; Return to caller if errors
ON_ERROR, 2
;
result = -1
;
usage = 'result = sst_correction_ncdf(yyyymmddb, yyyymmdde)'
nparam = N_PARAMS()
IF (nparam NE 2) THEN BEGIN
    ras = report(['Incorrect number of arguments.' $
          + '!C' $
          + 'Usage : ' + usage])
    return, result
ENDIF

; test if ${PROJECT_OD} defined
CASE project_id_env OF
    '' :  BEGIN
        msg = 'eee : ${PROJECT_OD} is not defined'
        ras = report(msg)
        return, result
    END
    ELSE : BEGIN
        msg = 'iii : ${PROJECT_OD} is ' + project_id_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)
    return, result
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)
    return, result
ENDIF
;
; build uncorrected t2 filename
filename_t2_uncor = 'erai_t2m_' $
    + string(yyyymmddb,format='(i8.8)') $
    + '_' $
    + string(yyyymmdde,format='(i8.8)') $
    + '_oafluxgrid.nc'
;
; check if this file exists
msg='iii : looking for ' + filename_t2_uncor
ras = report(msg)
fullfilename_t2_uncor = isafile(iodirout + filename_t2_uncor, NEW=0, /MUST_EXIST)
IF fullfilename_t2_uncor[0] EQ '' THEN BEGIN
   msg = 'eee : the file ' + fullfilename_t2_uncor + ' was not found.'
   ras = report(msg)
   return, result
ENDIF
;
; build output filename
filename_out = 'TropFlux_t2m_' $
    + string(yyyymmddb,format='(i8.8)') $
    + '_' $
    + string(yyyymmdde,format='(i8.8)') $
    + '.nc'
;
fullfilename_out = iodirout + filename_out
; in order to avoid unexpected overwritten
IF ((FILE_TEST(fullfilename_out) EQ 1)  AND (project_overwrite EQ 0)) THEN BEGIN
    msg = 'eee : the file ' + fullfilename_out  + ' already exists.'
    ras = report(msg)
    return, result
ENDIF
;
; define grid parameters with t2 file
initncdf, fullfilename_t2_uncor
;
; get time in t2 file
timein=ncdf_lec(fullfilename_t2_uncor,var='time')
jptin=n_elements(timein)
print, 'time steps from data ', jptin
print, 'The first 10 time values (variable timein) = ', timein[0:9]
;
; find first and last dates yyyymmdd
da=jul2date(julday(01, 01, 1957,timein[0]))
cda0=string(da,format='(i8.8)')
da=jul2date(julday(01, 01, 1957,timein[jptin-1]))
cda1=string(da,format='(i8.8)')
print, 'for time checking first date ', cda0
print, 'for time checking last date ' , cda1
;
; read t2 data
initncdf, fullfilename_t2_uncor
t2m=read_ncdf('t2m',yyyymmddb-.5d,yyyymmdde,file=fullfilename_t2_uncor,/nostr)
timein=24.d*(time-julday(1,1,1957,0,0,0))
jpt=n_elements(timein)
da=jul2date(time[0])
cda0=string(da,format='(i8.8)')
da=jul2date(time[jpt-1])
cda1=string(da,format='(i8.8)')
print, 't2m in t2m_correction_ncdf first date ', cda0
print, 't2m in t2m_correction_ncdf last date ' , cda1
;
t2m=t2m-273.15
help, t2m
;
jpt=jptin
t2m_mean=grossemoyenne(t2m,'t',/nan)
help, t2m_mean
;
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,jptin-1 do begin
    caldat, julday(01, 01, 1957,timein[jt]),mon,day,yea
    ;++print,day
    jtt=(julday(01, 01, 1957,timein[jt])-julday(1,1,yea)) < 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 variability 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 variability 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])
;
ncfile='!' + fullfilename_out
;
ncdf_getatt, fullfilename_t2_uncor, 'longitude', units=units
ncdf_getatt, fullfilename_t2_uncor, 'longitude', long_name=long_name
lon_attr={units:units, long_name:long_name}
ncdf_getatt, fullfilename_t2_uncor, 'latitude', units=units
ncdf_getatt, fullfilename_t2_uncor, 'latitude', long_name=long_name
lat_attr={units:units, long_name:long_name}
time_attr={units:'days since 1950-01-01 00:00:00',long_name:'Time axis',time_origin:'1950-JAN-01 00:00:00'}
globattr={source:'Basic data obtained from ERAI.  Mean correction for air temperautre bias and correction for variability are applied',timerange:cda0+' - '+cda1}
ncdf_getatt, fullfilename_t2_uncor, 't2m', units=units
ncdf_getatt, fullfilename_t2_uncor, 't2m', long_name=long_name
t2m_attr={units:units,missing_value:1.e20,long_name:long_name,short_name:'t2m',axis:'TYX'}
;
ncfields = 't2m[longitude,latitude,*time]=t2m_new:t2m_attr; ' $
                      + 'longitude[]=lon:lon_attr; ' $
                      + 'latitude[]=lat:lat_attr; ' $
                      + 'time[]=timein:time_attr ' $
                      + ' @ globattr'
;
@ncdf_quickwrite
;
result = 0
return, result
;
end