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TOPEX/Poseidon: Perspectives on an Ocean Planet

- Data Flow

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Data from the altimeter are stored in on board tape recorders and played back daily to control and processing centers at JPL and Toulouse, France. Mission data from TOPEX/Poseidon are available for science analysis within seven days of playback. During this time, the raw data used to produce ocean topography are corrected for instrument biases, tropospheric delay, ionospheric delay, electromagnetic bias, and tides. The sum of all these corrections can make a difference on the order of 2.5 meters in the measured ocean topography.

After correction, mission data are distributed to the Science Working Team for interpretation. The team is composed of 38 groups of scientists from the United States, France, Japan, Australia, South Africa, Germany, Norway, the Netherlands, New Caledonia and the United Kingdom. The principal products generated from these data are the Sensor Data Record or SDR, and the Geophysical Data Record or GDR. The GDR contains information on sea surface height, sensor corrections and geophysical information and is the key product for scientific analysis.

After production and verification, GDRs are sent to the Physical Oceanography Distributed Active Archive Center or PO.DAAC for distribution and archiving. Also archived is the Merged Geophysical Data Record. This product combines GDR data from both CNES and JPL.