A Mostly Quiet Pacific

Some climate forecast models indicate there is an above average chance that there could be a weak to borderline El Niño by the end of November 2003. However, the trade winds, blowing from east to west across the equatorial Pacific Ocean, remain strong. Thus, there remains some uncertainty among climate scientists as to whether the warm temperature anomaly will form again this year. The latest remote sensing data from NASA's Jason satellite show near normal conditions across the equatorial Pacific. There are currently no visible signs in sea surface height of an impending El Niño.

This equatorial quiet contrasts with the Bering Sea, Gulf of Alaska and U.S. West Coast where lower-than-normal sea surface levels and cool ocean temperatures continue (indicated by blue and purple areas).

The image above is a global map of sea surface height, accurate to within 30 millimeters. The image represents data collected and composited over a 10-day period, ending on Nov. 3, 2003. The height of the water relates to the temperature of the water. As the ocean warms, its level rises; and as it cools, its level falls. Yellow and red areas indicate where the waters are relatively warmer and have expanded above sea level, green indicates near normal sea level, and blue and purple areas show where the waters are relatively colder and the surface is lower than sea level. The blue areas are between 5 and 13 centimeters (2 and 5 inches) below normal, whereas the purple areas range from 14 to 18 centimeters (6 to 7 inches) below normal.

The Jason satellite carries a dual-frequency radar altimeter. This instrument beam microwave pulses-at 13.6 and 5.3 Gigahertz, respectively-downward toward the Earth. To determine the ocean's height, the instrument precisely measures the time it takes for the microwave pulses to bounce off the surface and return to the spacecraft. This measure, multiplied by the speed of light, gives the range from the satellite to the ocean surface. (For more details, visit the Jason Website.)