FOR RELEASE: October 17, 1997
Contact: Contact Stephen Loy 504 388-8654 [email protected]
Jay Grymes 504 388-6870 [email protected]
BATON ROUGE -- The Gulf Coast may experience a cooler and wetter winter and spring than normal because of the weather phenomenon called El Nino, but not necessarily, says Louisiana State Climatologist Jay Grymes.
"On average, El Nino years are wetter than normal. But remember that ëon average' doesn't mean every year. So you can't say that El Nino years are automatically wetter than normal," Grymes said.
El Nino is the unusual warming of waters in the central and eastern tropical Pacific, occurring on an irregular cyclical basis anywhere from two to seven years.
He said that El Nino may even affect the Gulf Coast's hurricane season.
"The El Nino can result in changes in weather across the globe. Wet and dry zones have shifted, particularly along the equator. For example, the East Indies and northern Australia, areas that normally are very wet, are suffering through a drought. By contrast, one of the driest deserts in the world--South America's west coast--is getting ample rain."
But El Nino isn't all bad. Drier than normal weather over Africa, as a result of El Nino, tends to be related to a decrease in tropical waves. Preliminary studies suggest that when western Africa is in a dry spell, fewer tropical systems develop in the Atlantic, a "positive" aspect of the Pacific phenomenon, he said.
"Even though El Nino has been mentioned in written history for more than 400 years, and native South Americans knew about it years before that, we still don't have enough data to accurately predict world-wide change in weather patterns caused by El Nino," Grymes said.
What oceanographers, climatologists and atmospheric scientists do know is that changes in water temperature in the Pacific Ocean are linked to changes in atmospheric pressure patterns across the globe.
"This is important because we know that the atmosphere works like a river of air. Changes in the atmosphere upstream are going to cause changes downstream. Just like rivers. It's these changes upstream (over the Pacific) that create climatic changes here in the Gulf Coast and all over the world," he said.
Scientists know that the ocean and the atmosphere work in tandem with circulation patterns, one affecting circulation in the other. By changing the water temperatures in the Pacific, both the oceans and the atmosphere undergo adjustments from their "normal" patterns.
Although some studies have been performed by a few experts in the 1960s and 1970s, scientists didn't start paying close attention to the effects of the phenomenon until recently. It was the 1982-83 El Nino, the strongest El Nino of this century, that really initiated serious research into the global responses of the warm-water event. "And it's only been since the 1982-83 El Nino that we really started studying the domino-like effects that come with this weather phenomenon," Grymes said.
"Often we are talking only a few degrees in terms of warmer waters, but in this El Nino, the waters are as much as nine degrees warmer than normal. Now, nine degrees difference in a sink or bathtub may not be so impressive, but it takes a lot of energy to warm waters that much over an area of the Pacific which amounts to something like twice the size of the continental United States," Grymes said.
Because of the dry weather over the past several months, Grymes said that southeast Louisiana and other parts of the Gulf Coast are probably in good shape to ride out El Nino. But he is quick to point out that the current dry weather is not El Nino-related.
"This area has recently seen unusually dry conditions in July and August, usually one of the wettest times of the year. The extra rain that may be caused by El Nino won't be as devastating, since the ground isn't saturated. But this region is also used to five to seven inches of rain at one time. While these intense rainfalls can cause damage, we are probably the most adept in the country to handle this much rainfall at one time.
"I try to steer people away from jumping to conclusions about El Nino. We just don't have enough data to make a lot of predictions and connections to El Nino yet," Gyrmes said.
El Nino was the topic of discussion at a roundtable recently hosted by the local chapter of the American Meteorological Society. The society is run through LSU's Southern Regional Climate Center. Grymes, along with Keith Henderson, a climatologist in LSU's Geography & Anthropology Department, S.A. Hsu, a marine meteorologist in LSU's Coastal Studies Institute, Jeff Hardy, a doctoral candidate in climatology, and other state and local experts participated in the El Nino discussion. - 30 -
If you need an expert to comment on El Nino:
Jay Grymes Grymes is Louisiana's State Climatologist. The office maintains records--both past and present--of all weather data (including data associated with El Nino) in the state, monitors and interprets all weather records, and disseminates the information to a broad range of users. LSU's Southern Regional Climate Center is housed with the Office of State Climatology. The climate center studies a six-state area that extends from Tennessee to Texas.
504-388-6870 (work) [email protected]
Keith Henderson Henderson has followed this year's El Nino closely and is familiar with the works of others. The work he has done with colleagues at the Southern Regional Climate Center concerns the impact of El Nino on Louisiana's climate. The most significant signal seems to be an increase in winter rainfall associated with more frequent fronts and Gulf storms, he said. Not every El Nino is the same, though, so it is difficult to extrapolate one event to another, Henderson said.
504-388-6137 (work) 504-338-0569 (home) [email protected]
Masamichi Inoue Inoue is a physical oceanographer interested in the large scale processes responsible for the generation of El Nino, the propagation of the signal throughout the Pacific Ocean, and its far-field effects. He has written and published on numerical models of El Nino.
388-2521 (Office) 767-5365 (Home) [email protected]
S. A. Hsu Hsu is a coastal meteorologist who is interested in meso-scale weather patterns along coastal regions, particularly in the northern Gulf of Mexico and studies air and sea interaction. Hsu has also created a new formula for predicting wave heights, like those due to hurricanes.
388-2962 (Office) 766-5195 (Home) [email protected]
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