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Ocean Surface Topography from Space
TOPEX/Poseidon shows unusual Pacific
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December 04, 1998

This image of the Pacific Ocean was produced using sea-surface height measurements taken by the U.S.-French TOPEX/Poseidon satellite. The image shows sea surface height relative to normal ocean conditions on November 29, 1998; these sea surface heights are an indicator of the changing amount of heat stored in the ocean. The image shows that an unusual large-scale warming (shown here in red and white) of the western Pacific first observed in early November has spread to the central Pacific. The low sea level or cold pool of water commonly referred to as La Nina, shown in purple, has remained essentially the same, changing very little in size and heat content. Oceanographers believe that the coexistence of these two contrasting conditions -- cooler water along the equator and warmer water in both the northern and southern hemispheres -- indicates that the ocean and
the climate system have not recovered from the record-breaking warming that has occurred during the past two years. The purple areas are 14 to 18 centimeters (6 to 7 inches) below normal and the blue areas are 5 to 13 centimeters (2 to 5 inches) below normal. The white areas show the sea surface is between 14 and 32 centimeters (6 to 13 inches) above normal; in the red areas, it is about 10 centimeters (4 inches) above normal. The green areas indicate normal conditions.

For more information, please visit the TOPEX/Poseidon project web page at

Source: Jet Propulsion Laboratory

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