This image from the TOPEX/Poseidon satellite shows preliminary results of wave height over the global ocean as measured by the Ku-band NASA radar altimeter. The data were recorded from Sept. 25 to Oct. 4, 1992. The highest waves were observed in the Southern Ocean south of South Africa and Australia, where giant waves as high as eight meters (26 feet) were recorded. These waves are shown in red. (The small pink square on the shoreline of Antarctica is an artifact of the processing.) The pattern of wave height is dependent upon the season. The highest waves tend to occur in winter and the lowest waves in summer. The time of this observation was during the transition of winter to spring in the Southern Hemisphere. Wave height is one of the oceanographic measurements made by the TOPEX/Poseidon satellite. It is determined by the shape of the return radar pulse. A calm sea with low waves returns a condensed pulse, and a rough sea with high waves returns a stretched pulse. Calibration and validation of the altimeter observations against ground truth measurements will be conducted over the next few months. TOPEX/Poseidon, a joint U.S./French mission, is part of NASA's Earth Science and Application Division. Launched Aug. 10,1992, it is the second satellite in the Mission to Planet Earth program, a long-term effort to study Earth from space.
