Pacific Recycles Last Year's Winter

The Pacific ocean continues to be dominated by the Pacific Decadal Oscillation, an above normal sea level pattern that is larger and stronger than any El Nino/La Nina event, according to the latest information from the U.S.-French Topex/Poseidon ocean-monitoring satellite.

"It is striking how similar October 2001 looks to October 2000," said Dr. William Patzert, an oceanographer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Last winter the weather- and moisture-delivering jet stream was steered north by this pattern, resulting in a very chilly, stormy winter in the Midwest and continuing drought on the West Coast."

"Looks like a repeat performance to me," Patzert added.

The Topex/Poseidon data were taken during a 10-day collection cycle ending Oct. 29. They show that the near-equatorial ocean has been very quiet during the past year, and sea levels and sea surface temperatures are near normal. Above normal sea surface heights and warmer ocean temperatures still blanket the far western tropical Pacific and much of the north mid-Pacific.

In the western Pacific, the buildup of the Pacific Decadal Oscillation, first noted by Topex/Poseidon oceanographers more than three years ago, has outlasted both the El Nino and La Nina of the past several years. This warmth contrasts with the Bering Sea, Gulf of Alaska and West Coast, where lower than normal sea surface levels and cool ocean temperatures continue.

"There will be winners and losers in the next few months," said Patzert. "The upper and lower Midwest should expect intermittent blizzards, and the West Coast and Southwest a continuation of below normal rainfall. The outlook is not extreme nor catastrophic."

These data are in line with the U.S. winter forecast issued by the National Oceanic and Atmospheric Administration's National Weather Service. They also show a repeat of last winter's chill across the northern states and relative warmth across the South, with continuing drought in the southeastern states and possibly the western states.

"Next month's launch of the Jason 1 satellite will continue the revolutionary Topex/Poseidon data-gathering with a smaller satellite based on new technologies," said Dr. Lee-Lueng Fu, the Topex/Poseidon and Jason 1 project scientist at JPL. "It will further improve the understanding of ocean circulation and global climate forecasts, as well as provide a key step towards making sea surface height measurement a permanent component of a global ocean observing system in the future."

The joint U.S.-French Topex/Poseidon mission and the Jason 1 program are managed by JPL for NASA's Earth Science Enterprise, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. For more information on Topex/Poseidon, see http://topex-www.jpl.nasa.gov . The October 2001 Topex/Poseidon image is at http://www.jpl.nasa.gov/images/earth/pacificocean . Last year's October pattern is at http://hail/Datasets/links/hail/air7/akh/TPimages/2000/oct2000_ball.gif . NOAA seasonal weather forecasts are available at http://www.noaanews.noaa.gov/stories/s794.htm . Information about Jason 1 is available at http://sealevel.jpl.nasa.gov .