February 2, 2010

Europe Secures Funding For Jason-3 Surface Height Mission

In an effort to monitor the behavior of the world's oceans, Europe has committed to build the next Jason altimeter spacecraft -- a decision that should guarantee the continuation of a remarkable 18-year record of sea-surface shape until late in the decade, BBC News reported.

The recent steady 3mm per year rise in global sea level has been tracked by the Jason series. The data has become invaluable to oceanographers, weather forecasters and climatologists.

Eumetsat, which looks after Europe's meteorological satellites, has indicated that its member states will now meet their 25 percent share of the $380 million project. The U.S. and France are picking up most of the remainder of the mission cost, with the latter providing the spacecraft bus, or chassis, through Thales Alenia Space.

Pending time to crosscheck its data in orbit with the current Jason-2 observatory, Jason-3 should launch in 2013. Scientists can only minimize calibration errors between the two satellites' datasets by flying the pair in tandem for a period of months.

Experts say having ocean surface elevation data has many and varied applications, both short-term and long-term. Just as surface air pressure reveals what the atmosphere is doing up above, so ocean height will betray details about the behavior of water down below.

Researchers will be able to collect clues on temperature and salinity and when combined with gravity information, it will also indicate current direction and speed.

Jason will monitor the progress of the El Nino phenomenon, which sees an eastward shift in warm water across the central Pacific Ocean. The movement is evident to Jason in an anomalous rise in sea surface height as the changes in temperature make the ocean bulge.

Global weather systems are very influenced by El Nino, dramatically altering precipitation patterns.

Jason provides the global reference against which all other ocean topography datasets are matched, but many in the Earth observation community feared the global financial crisis might limit European nations' ability to fund Jason-3.

However, in order to obtain the "essential climate variables" - to acquire the key pieces of information that reveal the true state of the planet, the EU, the European Space Agency and Eumetsat are all working together.

In order to make that happen, the satellites must gather continuous, cross-calibrated, long-term datasets.

There is a good chance that the ocean topography sequence started in 1992 will now be maintained with the initiation of Jason-3.

The agencies have even started discussions about a "Jason Continuity" mission, which would probably see an altimeter put on a spacecraft bus similar to the one being used on the forthcoming Cryosat mission "“ which is set to launch at the end of this month to gather information about the state of the Earth's ice fields.

Science Minister Lord Drayson said the UK contribution was vital to the future of the Jason series and the crucial data it provides on sea-surface height across the globe.

"We are committed to the Jason-3 satellite," he said.

He explained that the measurements are critical to monitoring the effects of climate change and to safe exploitation of the marine environment.

"The government is determined to ensure the program continues to deliver these to researchers for years to come as we strive to tackle global warming," he said.


Image Caption: Artist's interpretation of the Jason-2 satellite.


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