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Teams of high school and junior high students will launch buoys into Galveston Bay, Texas, to verify altimeter measurements from the TOPEX/Poseidon satellite in an experiment that will help oceanographers better understand ocean dynamics and calculate global sea level rise.

NASA's Jet Propulsion Laboratory-sponsored buoy "float-off" will take place at 10 a.m. Central Time on Wednesday, May 15, in Galveston Bay, near Eagle Point, Texas.

Each team of students has designed and built their own buoy and each buoy is equipped with a Global Positioning System (GPS) receiver which helps the students precisely track its location. The buoys will record sea level and wave height measurements along a track on the water as TOPEX/Poseidon flies overhead. This information will be used in conjunction with data from several tide gauges in the area to validate the satellite's performance.

GPS is an array of 24 satellites that was originally developed by the U.S. Department of Defense. By measuring signals from these satellites, users can pinpoint their precise location almost anywhere on Earth.

"It's crucial that we have continuing calibration of the satellite's altimeter height measurements to help us determine if the global sea level is rising," said Dr. George Born, a TOPEX/Poseidon science team member at the University of Colorado, Boulder. "Locally, verifying the measurements of sea level in Galveston Bay will prove useful in improving tide models by providing a reality check."

"Galveston Bay is an ideal site for us to conduct this experiment. As the TOPEX/Poseidon satellite passes directly over the center of the bay, there are numerous tide gauges to further verify the measurements and relatively low waves," said Amy Neuenschwander of the University of Texas Center for Space Research (UTCSR). "This bay is Texas' most important coastal environment, containing natural resources which are self-renewing as long as the bay remains healthy and productive."

"Improved tide and circulation models will improve the ability to track pollutants such as oil spills in the bay as well as improving biological models," Born added. "Hence, the experiment has the long-term potential of contributing to the maintenance of a healthy ecosystem in the bay."

The "float-off" is part of an on-going educational outreach program between JPL, UTCSR and the Texas Space Grant Consortium (TSGC), in conjunction with the Colorado Center for Astrodynamics Research (CCAR) and the Colorado Space Grant Consortium (CSGC). The Texas students are from two Houston area high schools, Friendswood and Pearland, and one middle school, Seabrook Intermediate. The Colorado students are from Boulder High School and the University of Colorado.

TOPEX/Poseidon, a joint program of NASA and the Centre National d'Etudes Spatiales, the French space agency, uses a radar altimeter to precisely measure sea-surface height. Launched in August 1992, the satellite measures the sea-surface with an unprecedented accuracy of less than 5 centimeters.

TOPEX/Poseidon is part of NASA's Office of Mission to Planet Earth, a coordinated, long-term research program to study the Earth as a global system. TOPEX/Poseidon's sea-surface height data are essential to a better understanding of the role oceans play in regulating global climate, one of the least understood areas of climate research.

The Jet Propulsion Laboratory manages the U.S. portion of the TOPEX/Poseidon mission for NASA.

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