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 8, 1998; these sea surface heights are an indicator of the changing amount of heat stored in the ocean. The image shows that the low sea level or cold pool of water commonly referred to as La Niña, shown in purple, has stayed about the same for the last five months changing very little in size and heat content. The satellite's ability to monitor the entire ocean indicates there is also a large-scale warming taking place in the western Pacific, shown here in red and white. 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 http://topex-www.jpl.nasa.gov