README of NASA-NASDA OCTS Level 3 Binned Map data (EORC 2byte binary version)
  16 May 2002

1. Description

NASA and NASDA developed a new OCTS algorithms based on the latest SeaWiFS one,
and NASA produced OCTS global products (Level 2, Level 3 Binned, Level 3 SMI).
EORC made binary data sets mapped from the Level 3 Binned data.


2. Data parameters, slope and unit

Parameter codes, parameters, slopes and units are listed in below.

L412  normalized water leaving radiance at 412nm, 0.00020, [mW /m^2 /str /um]
L443  normalized water leaving radiance at 443nm, 0.00020, [mW /m^2 /str /um]
L490  normalized water leaving radiance at 490nm, 0.00020, [mW /m^2 /str /um]
L520  normalized water leaving radiance at 520nm, 0.00020, [mW /m^2 /str /um]
L565  normalized water leaving radiance at 565nm, 0.00020, [mW /m^2 /str /um]
L670  normalized water leaving radiance at 670nm, 0.00005, [mW /m^2 /str /um] 
CHLO chlorophyll-a concentration                , 0.00050, [mg /m^3         ]
T865 aerosol optical tickness at 865nm          , 0.00005, [                ]
ANGS aerosol angstrom expornent (8day and month), 0.00010, [                ]

3. Data format

Files in the EORC server are formatted as follows.
[2-byte unsigned integer] x [4096 pixel] x [2048 line]

DN can be converted to the physical values by the following equation.
CHLO:
[physical value] = 10.0^([2-byte DN] x [slope] -bias)
others:
[physical value] = [2-byte DN] x [slope]

Missing value:
DN=0

Area coverage:
Pixel center starts from -180+360deg/4096/2=-179.956degE 
to eastward until 179.956degE.
Lines starts from 90-180deg/2048/2=89.956degN to -89.956degN.

Spatial resolution:
360deg/4096=0.08789 (LON) x 0.08789 deg (LAT)

Temporal resolutions:
daily, 8 days and monthly. 

---------------------------------------
c    f77 -bytereclen test.f
c
c    Example of reading CHLO value by FORTRAN
c
      parameter(nl=4096, ml=2048)
      integer*2 idat(nl,ml)
      integer*4 idat4
      real*4     rdat, slope
c
c     slope for CHLO
      slope=0.00050
c
      open(10,file='month/O19970011997031.L3M_MO_CHLO',
     & form='unformatted',recl=nl*2,access='direct',status='old')
c
      do m=1,ml
       read(10,rec=m) (idat(n,m),n=1,nl)
      enddo
c
      close(10)
c
      write(6,*) 'type grid n'
      read(5,*) n
      write(6,*) 'type grid m'
      read(5,*) m
c
      if(idat(n,m).lt.0) then
       idat4=65536+idat(n,m)
      else
       idat4=idat(n,m)
      endif
c
      if(idat4.gt.0) then
       rdat=10.**(idat4*slope-2.)
      else
       rdat=-999.
      endif
c
      write(6,'(a16,f10.5,a2,2(i4,a1))') 
     &      'Data at [n,m] = ',rdat,' [',n,',',m,']'
c
      stop
      end
c

** Compile:
 SGI: f77 test.f -bytereclen
 SUN: f77 test.f


c
----------------------------------------


4. credits

This data set was created by a collaboration of the NASA SeaWiFS and SIMBIOS Projects and NASDA.
When you use the OCTS data and images in publications, please include credits like follows.

"The SIMBIOS-NASDA-OCTS Data was created and supplied by the NASA SeaWiFS, SIMBIOS Projects and NASDA OCTS project."

Also, we would appreciate receiving a preprint and/or reprint of those publications utilizing the data for inclusion in the ADEOS OCTS bibliography. These publications should be sent to: 

The EORC ADEOS Office
Earth Observation Research Center
National Space Development Agency of Japan
Harumi-Triton X-tower 23F,
1-8-10, Harumi, Chuo-ku, Tokyo 104-6023, JAPAN

or 

FAX: +81-3-6221-9191
E-mail: adeossupport@eorc.nasda.go.jp


5. Contact

Please contact us for any comments, problems or questions at e-mail address:  adeossupport@eorc.nasda.go.jp