Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, January 25, 1995 TAG: 9501250081
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: ASSOCIATED PRESS
DATELINE: LOS ANGELES LENGTH: Medium
The weather-influencing El Nino phenomenon, a warming trend in the water of the tropical Pacific, is twice as strong now as it was in 1992-93, NASA reported Tuesday.
The French-U.S. TOPEX-Poseidon ocean-observing satellite has detected a marked rise in sea surface elevation in the area, an indication of higher-than-expected water temperatures, said Lee-Lueng Fu, a project scientist at NASA's Jet Propulsion Laboratory.
Although the common U.S. weather disturbances from an El Nino include milder temperatures in the Northeast, as seen this winter, Fu said it is not the only factor to blame for this winter's heavy rain and flooding in California.
JPL released satellite images of the warmed, expanded water layer moving eastward during October, November and December, when it reached the coast of South America.
The satellite's radar images show the tropical Pacific is about 4 inches to 8 inches higher than normal, project scientists said.
During the 1992-93 El Nino, it was 2 inches to 4 inches above normal, Fu said.
That earlier El Nino ``was a significant event that caused large changes in the jet stream over the Pacific and North America through May 1993,'' said Gerald Bell, a meteorologist with the National Weather Service Climate Analysis Center in Camp Springs, Md. ``California got pummeled with rainfall that ended a long-term severe drought. South Africa got hot and dry. The El Nino was an indirect contributor to the Midwest floods.''
But, he cautioned, ``a stronger El Nino doesn't necessarily correspond to stronger rainfall and temperature anomalies.''
The extra height measured during both El Ninos reflects ``an excessive amount of unusually warm water in the upper ocean,'' Fu said.
That excess heat can affect weather worldwide by heating the atmosphere and altering the atmospheric jet stream, Fu said.
The result is a disruption of global weather patterns.
El Nino, a characteristic warming of surface water in the tropical Pacific, occurs when westward trade winds weaken and the warm water mass, called a Kelvin wave, begins moving eastward along the equator.
``This wave is currently occupying most of the tropical Pacific Ocean,'' Fu said Monday. ``It will take another month or two before the wave disperses.''
by CNB