These measurements, also known as ocean surface topography, provide information on the speed and direction of ocean currents. Because sea surface height is strongly influenced by the amount of heat in the ocean, it also is an indicator of ocean heat storage in most places. Combining ocean current and heat storage data is key to understanding global climate variations.
OSTM/Jason 2 marks the transition of high-precision altimetry data collection to the world's weather and climate forecasting agencies. Scientists soon will be able to forecast how ocean circulation will change from one season to the next and how that circulation is linked to climate change and weather patterns.
"What began as an investment by NASA and CNES in research tools for studying the ocean has matured into a proven technique that will now be routinely used by the world's weather and climate agencies to make better forecasts," said Michael Freilich, director of the Earth Science Division in NASA's Science Mission Directorate in Washington.
"People in coastal areas will benefit from improved near-real-time data on ocean conditions, while people everywhere will benefit from better seasonal predictions resulting from the increased understanding of Earth system processes enabled by these measurements," he said.
OSTM/Jason 2 and Jason 1 will fly in formation, making nearly simultaneous measurements. For six to nine months after launch, scientists will verify whether the instruments are calibrated precisely. OSTM/Jason 2 then will continue Jason 1's former flight path, and Jason 1 will move into a parallel ground track midway between two of the OSTM/Jason 2 ground tracks.
This tandem mission will double the amount of data collected, further improving tide models in coastal and shallow seas and helping researchers better understand ocean currents and eddies. OSTM/Jason 2's mission is designed to last at least three years.
The OSTM/Jason 2 spacecraft, provided by the French Space Agency, carries five primary instruments similar to those on Jason 1. Its main instrument is the Poseidon 3 altimeter, also provided by the French Space Agency. NASA's Advanced Microwave Radiometer measures atmospheric water vapor, which can distort the altimeter measurements.