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TOPEX/POSEIDON Satellite Data for El Niņo
Helping predict future El Niņo events
Measuring Sea Level
TOPEX/POSEIDON's orbit is measured precisely by using two ground-based systems plus a
Global Positioning System (GPS) tracking system. The satellite's altimeter bounces radar
signals off the surface to determine sea-level height. Gravity's influence on the shape of
the ocean is subtracted from the data to obtain the ocean topography created by currents.
Thanks to NASA/JPL/Caltech for this image.
In a normal year, the strong trade winds to the west push warm surface water against the
western boundary of the Pacific Ocean near Australia and Indonesia, while nutrient rich
cold water wells up along the west coast of South America, helping fish thrive.
TOPEX/POSEIDON has tracked this building up of warm water in the western Pacific Ocean,
which can be as much as 1 meter higher than the eastern Pacific.
The trade winds are controlled by an air/sea interaction in which SST (Sea Surface
Temperature) plays a huge part. In an El Niņo year, these trade winds weaken causing
upwelling to decrease which in turn suppresses the upwelling of cold water. Thus, the
thermocline deepens as a result of the Kelvin and Rossby Waves. [If you do not fully
understand this succession of events, please go back to our overview and after reading
those sections, come back here.]
Media | The TOPEX/Poseidon Satellite..in action!
See the TOPEX/Poseidon Satellie in 3-D simlutated Action.
Quicktime Movie
Thanks to Susan Gee from NASA/JPL/Caltech
All of this has been measured by TOPEX/POSEIDON during El Niņo events since 1992. The
image at the bottom is an actual image of TOPEX/POSEIDON satellite data.
Media | The Launch of the TOPEX/Poseidon Satellite
See or Hear the exciting launch of the TOPEX/Poseidon Satellie from French Guyana on
August 10, 1992. Those of you who don't understand French will not have trouble following
the countdown we hope!
Quicktime Movie
Real Audio
Thanks to Susan Gee from NASA/JPL/Caltech
Using TOPEX/POSEIDON data, scientists are working to improve the performance of such
models, with the goal of reliably predicting climatic many events, not just the dreaded El
Niņo.
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