A NASA study suggests changing winds and currents in the Indian Ocean during the 1990s contributed to the observed warming of the ocean during that period. The findings, published in a recent issue of Geophysical Research Letters, have potential implications for long- term regional climate variability. “Establishing this correlation provides an important missing piece to the global ocean-warming puzzle and provides vital information for regional governments and climate modelers,” said Dr. Tong Lee, study author and researcher at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. “These findings from satellite data also advance space exploration by increasing understanding of how complex planetary system elements, such as winds and currents, in our home planet interact to drive climate change. Such technologies, which have been demonstrated to be critical in understanding Earth’s climate system, may someday prove useful in studying climate systems on other planets,” he said.
Lee’s findings are based on sea level measurements from NASA’s Topex/Poseidon oceanographic satellite, sea-surface temperature data from the National Oceanic and Atmospheric Administration’s Advanced Very High Resolution Radiometer satellite, and wind data from the European Space Agency’s European Remote Sensing satellites. Collected between 1992 and 2000, the combined data reveal weakening of southeasterly trade winds over the South Indian Ocean caused a major circulation of this ocean to wane by nearly 70 percent of its average strength. The atmosphere heats the upper Indian Ocean. The circulation of this ocean counteracts the atmospheric heating by exporting warm surface water and importing colder subsurface water.