Tracking That Crazy Weather

By Frederic Golden

IT may all be linked to a warm current off South America

Meteorologists have a saying: "There is no such thing as really abnormal weather." But even seasoned scientists have been astounded by the extremes of this year's weather. While winds, rains and high seas have lashed California, much of the rest of the U.S. has basked in an exceptionally mild winter. In Australia, usually drenched by rain during the Southern Hemisphere's autumn, there has been a drought that has been called the worst in 200 years. In the eastern Pacific, Peru, Bolivia and Ecuador have been staggered by record rains, floods and landslides that have cost hundreds of lives and millions of dollars.

All this could perhaps be dismissed as a climatological quirk, if it were not accompanied by other baffling events. On Christmas Island in the mid-Pacific, about 17 million sea birds have fled their ancient nesting grounds. Barracuda are unexpectedly appearing in the waters off Monterey, Calif. Marlin, red crabs, sea horses and other creatures usually found in warm Mexican waters are showing up as far north as San Francisco. High in the sky, westerly winds have been blowing so furiously toward the California coast that jets have cut their flying time from Hawaii by as much as an hour.

Many scientists believe there is a common thread in this crazy-quilt weather, some fair, some foul, some just puzzling. It is a phenomenon known in Spanish as El Nino, a reference to the Christ child. Named by the fishermen of Peru and Ecuador, El Nino is a warm current of equatorial water that usually appears around Christmas off western South America. The peculiar ocean movement sharply reduces the fish catch, especially anchovies, which are ground up and sold as meal for livestock and poultry. The present El Nino, which first appeared last June and has raised ocean surface temperatures by as much as 11DEG F, is no ordinary one. Says Meteorologist Jerome Namias of the Scripps Institute of Oceanography in La Jolla: "This is probably the strongest El Nino we've ever seen."

The waters off Peru and Ecuador are usually an exceptionally rich fishery. As the cold Humboldt Current sweeps north from the Antarctic, it lifts a rich mix of nutrients from the ocean floor that lets a variety of marine life flourish. In 1970, Peruvian fishing boats called bolicheras (from the Spanish word for dragnet) hauled in 13 million tons of anchovies, a fifth of the world's total fish catch. Now, the warm equatorial water is blocking the upwelling of nutrients from the sea bottom. The result is economic disaster. The anchovies are largely gone. Coastal waters have turned into a sludge of rotting plankton and fish. Sea birds, whose droppings (guano) are an important source of fertilizer, are dying off for lack of food. When the last severe El Nino struck in 1972, the reduced catch of the cheap anchovies raised poultry prices in the U.S. by more than 40%.

But as scientists study El Nino, they are finding that it is really a much broader disturbance of ocean currents and winds that ranges far across the Pacific and even beyond. One aspect of this larger phenomenon is an event weather scientists call the southern oscillation, a flip-flop-like reversal of atmospheric pressures at opposite sides of the great ocean. At this time of year, a great, spongy mass of warm, wet air ordinarily hangs over Australia and Indonesia, while the eastern side of the Pacific is covered with relatively dry, cool air. Not so in 1983. A high-pressure pattern is locked over Australia, while the South American coast is awash with heavy, humid air. Says Eugene Rasmusson, chief climate analyst of the National Oceanic and Atmospheric Administration (NOAA): "Every few years there is a seesaw effect, and there are dramatic results around the earth."

One of the oscillation's major effects is a reduction of the trade winds that sweep the Pacific's warm equatorial waters westward. As a result, some of the water flows south toward the South American coast, rising over and blocking the cold Humboldt waters from the Antarctic. This is how El Nino is born. But the oscillation also appears to tweak the Northern Hemisphere's weather as well. This year the increased west-to-east jet stream, which usually diminishes during winter, has raised sea levels 8 in. above normal and brought huge amounts of precipitation to California. While these byproducts are plain enough, the oscillation's original cause remains uncertain. In the past, scientists have speculated that it may be the work of sunspots (the magnetic storms on the face of the sun that periodically reduce its radiation) or even planetary alignments. Currently, much of the theorizing centers on El Chichon, the Mexican volcano that erupted last year and ejected huge clouds of dust into the atmosphere. By obscuring sunlight, it may have upset the planet's heat balance enough to disturb the atmosphere and oceans.

Whatever the explanation for this year's outbreak of crazy weather, scientists feel that the basic puzzle of El Nino and the southern oscillation is worth exploring. Last month more than 100 scientists gathered at Scripps to discuss the meteorological disturbances. The National Science Foundation is already spending $6 million for related oceanographic studies. Under consideration is a major, ten-year international investigation that would call for additional monitoring of Pacific water and atmospheric conditions. Scientists think that the money for the project would be well spent, since the events off South America affect not only local fishermen but much of the rest of the world. As NOAA's Rasmusson explains, "When one part of the atmosphere moves, another part feels the kick." This year the kick has been particularly powerful.

--By Frederic Golden. Reported by Jerry Hannitin/Washington and Russell Leavitt/Los Angeles

With reporting by Jerry Hannitin/Washington, Russell Leavitt/Los Angeles This file is automatically generated by a robot program, so viewer discretion is required.