ADEOS/OCTS Global Map Data Set (SST Ver.4.1) GAC L3BM Monthly; Weekly; Daily and Data

Introduction
This Advanced Earth Observing Satellite (ADEOS) / Ocean Color and Temperature Scanner (OCTS) Global Map Data Set CD-ROM is made for researchers of ocean science etc., by the Earth Observation Research Center (EORC), National Space Development Agency of Japan (NASDA).

ADEOS was developed with the aim of establishment of platform technology for future earth observation spacecraft and its data will contribute to research of the global environmental change by science community.

ADEOS/OCTS was a visible and infrared multi- spectral radiometer which NASDA developed to measure global ocean color and sea surface temperature with high sensitivity. Global ocean primary productivity and ocean current will be retrieved from OCTS data.

The instrument scanned the earth surface using a rotating mirror in the direction crossing the satellite flight path. In order to avoid sun glitter, it had a tilting mechanism.

The Major specification of OCTS was as follows.
Scanning Method ; Mechanical
Wavelength ; Visible 6 Bands
Near- infrared 2 Bands
Middle-infrared 1 Bands
Thermal-infrared 3 Bands
Spacial Resolution ; Approx. 680m at nadir

ADEOS was launched by H-II rocket from NASDA/Tanegashima Space Center, Japan on 17 August 1996 (JST), and continued its operation for about 10months, but ADEOS stopped its function on 30 June 1997 by malfunction of the Solar Array Paddle.

You can get more information about ADEOS and OCTS from the NASDA/EORC's WWW server of which address is http://www.eorc.nasda.go.jp/ADEOS/
Data contents
Within two pieces of CD-ROM, Vol.1 contains the Chlorophyll-a concentration (chl-a), Vol.2 contains the Sea Surface Temperature(SST) .

This CD-ROM contains the Sea Surface Temperature(SST) of the Global Area Coverage (GAC) browse and data, the ADEOS / OCTS Level 3 Binned Map data (Processed by Ver. 4.1 algorithm).

GAC Level 3 Binned Map data include Monthly , Weekly and Daily products and its Binary Data. These data are obtained during November 1996 to June 1997 by OCTS on ADEOS.

The CD-ROM directories are shown below.
	/------MENU.HTM
             |
             |-/BROWSE-----/MONTHLY------.gif,.tif file 
             |           |-/WEEKLY-------.gif,.tif file
             |           |-/DAILY--------.gif,.tif file
             |
             |-/DATA-------/MONTHLY------data file 
             |           |-/WEEKLY-------data file 
             |           |-/DAILY--------data file 
             |
             |-/DOC

    .tif : TIFF Browse 
    .gif : GIF Browse 
    data : tar(UNIX) archived and compressed Data  (.tar.Z)
Gif and tif files in BROWSE directory correspond to data files in DATA directory.

The Contents of browse and data are presented as follows:

OCTS Global Area Coverage (GAC) Level 3 Binned Map (L3BM) Data Processed by Version 4.1 algorithm
           Sea Surface Temperatude(SST) 
             Monthly Browse and data (1996/11 ~ 1997/06)
             Weekly Browse and data (1996/11/01 ~ 1997/06/29)
             Daily Browse and data (1996/11/01 ~ 1997/06/29)
[Note 1]
The Global Area Coverage (GAC) data are thinned to one-fifth of the original data volume along both pixel and line directions at the time of input with special care being paid to proper registration. The resolution of GAC data is approximately 4km at the nadir. The Binned data are arranged in terms of time and space. The bins are rectangular bins placed parallel to the equator and are divided along the longitude every one-twelfth of a degree on the equator. At each latitude, the number of bins is adjusted, so the area of each bin is almost equal (approximately 9km by 9km). In regard to Binned map, the Binned data are placed on a global map projected with equal latitude and longitude rectangles.

[Note 2]
TIFF and GIF data were browsed from the L3BM data to thin down the data volume and allocate visible color to each pixel's digital account for easy to handle and easy to realize. So, the resolution of TIFF and GIF data is about one-eighth and one-sixteenth of that of L3BM data respectively.

[Note 3]
Contents of the data directory are generated from some part of the HDF file of the original. The original data format is NCSA HDF. Those are archived by `tar` command into it. It includes several files as follows:
    *.log:   Global Attribute
    *.pal:   Color Palette (size:256x3(RGB))
    *.dat:   Raster Data (Raw Data)
Data projection and conversion method to physical value of L3BM *.dat file is as follows:
        Format
            size: 4096x2048, 1 byte per pixel
            header size: 0
            area: 90N to -90N (North -> South), 
                  -20E to -20E (West -> East)
       The conversion of Lat,Lon - Line(m),Pixel(n)
            Lon E  =160+360/4096*(n-2048.5), n=1....4096
            Lat N  =180/2048*(1024.5-m), m=1....2048
       Physical Value
          SST (Sea Surface Temperature)
            Count_Value (1byte unsigned integer)
            Physical_Value = Product_Count x Slope + Intercept
            Slope = 0.15
            Intercept = 271.15
            Unit = kelvin
How to use this CD-ROM
This CD-ROM requires no installation to your PC or workstation. No software resides on this disk. It functions equally well on PC (running Windows 3.1/95/NT/98) Mac (PowerPC or non-powerPC), or UNIX computers. A World Wide Web (WWW) browser is recommended.

This CD-ROM's data are made into GIF and TIFF browse. This CD-ROM also contains documentation about the data, as well as directives so that you can find the browse that you desire to see.

The documentation on this CD-ROM is written in HTML. So, you should use a web browser to view this documentation. We recommend you to use either Netscape navigator version 3.0 or higher, or Microsoft internet explorer version 4.0 or higher. Both of these programs are available at no cost at their web site :
(Netscape : http://home.netscape.com/ ;
Microsoft : http://www.microsoft.com/ )

The browse on this CD-ROM is in the Monthly, Weekly and Daily folder of this disk. They may be retrieved directly from the data folder as well as through the HTML documentation.
Naming Convention
     TyymmddP 
           T --- Data sub-Type 
               O : Ocean Color Chlorophyll-a concentration 
               S : Sea Surface Temperature
           yymmdd --- Observation Start Date 
               yy : Year (lower 2 digits) 
               mm : Month 
               dd : Day
           P --- Product Type 
               D : Daily 
               W : Weekly 
               M : Monthly
How To View The Retrieved Binary Data
You will get the tar archived data by the operations above. Before viewing the data, you have to follow the steps below to extract the files.
        yourprompt% mv data-file-name tar.Z-file-name
        yourprompt% uncompress tar.Z-file-name
        yourprompt% tar xvf tar-file-name
Now you can take a look at the data. When you want to view the raw data, you have to use the application that allows you to input the columns and lines of the data you want to view.(ex. PCIWORKS, IMAGINE, ...)
Matters that required attention about SST data

OCTS was in "Tilting" operation from 1 November to 18 December 1996, and from 19 March to 29 June 1997. The tilt angle was changed from 0 to -20, -20 to 20, and 20 to 0 degrees respectively when the satellite reaches above the points of about 60, 0, and -60 degrees north from the nadir of the sun to avoid sun glint in this period. The tilt changes seem to cause some SST bias in comparison with other data. These will disturb some analysis of the global and tropical SST except for in mid-latitude of the Northern Hemisphere. Applying regression formulas of the latitude of tilt switching, they will be improved. You can get more information from the NASDA/EORC's WWW server ( http://www.eorc.nasda.go.jp/ADEOS/UsersGuide/Doc_and_Paper/index.html).
You may find the error in SST data from 1 January to 1 February 1997. The trouble of one detector caused these error. Therefore, you need pay attention to that data.

Copyright
Images Copyright (c) 1996, 1997 NASDA, data receive and processing by NASDA/EOC, data set composed and CD-ROM made by NASDA/EORC.

If you wish to publish these images for scientific or educational purposes, no permission is required and there is no charge. Please acknowledge the origin of the data by adding "(c) NASDA " below any image published.

The data, images and text contained within this CD-ROM are only intended for scientific and/or educational use. Any other use is prohibited under the terms of the NASDA copyright.
NASDA                    EORC-035
=======================================================
NATIONAL SPACE DEVELOPMENT AGENCY OF JAPAN
OFFICE OF EARTH OBSERVATION SYSTEMS
EARTH OBSERVATION RESEARCH CENTER (EORC)
=======================================================
Earth Observation Research Center Roppongi First Building,
1-9-9, Roppongi, Minato-ku, Tokyo, 106 Japan 
Phone    +81-3-3224-7040
Fax      +81-3-3224-7051
E-mail   adeosdata@eorc.nasda.go.jp
URL      http://www.eorc.nasda.go.jp
========================================================

Earth Observation Research Center
Last Update: 22 March 2002

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