March 1, 2007 Researchers are using satellites in efforts to better predict El Niño, the weather pattern responsible for supplying more moisture and energy to storms in the U.S. during the winter season. El Niño develops when easterly trade winds -- that usually push warm waters west -- weaken, allowing warm water to spread east towards the Americas. Tracking El Niño from 1,300 kilometers in space, NASA's Jason satellite can help scientists better forecast El Niño’s likely effects on climate.
- El Niño-Southern Oscillation
- Atmospheric circulation
- List of Category 5 Pacific hurricanes
- 1997 Pacific typhoon season
Drenching rain ... Deadly tornadoes ... Wicked ice storms. 1998's El Niño was a huge force. So when El Niño surfaced again this winter, NASA climatologists and oceanographers jumped on his trail.
From 1,300 kilometers in space, satellite Jason tracks El Niño's return to the tropical Pacific, sending images every 10 days. El Niño develops when easterly trade winds that usually push warmer-than-normal sea waters west weaken, allowing warm water to spread east towards the Americas -- supplying more moisture and energy to storms in the United States.
"We did have severe droughts and fires in the western Pacific, but the impacts never really developed over the Americas," Bill Patzert, a climatologist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., tells DBIS.
Pasadena Fire Chief Dennis Downs was counting on El Niño rains to reverse California's record dry spell. "There's no chance to catch up," he says. "So what you're looking at now is a tinder box just waiting to go up."
And that means firefighters can expect a busy year.
Across town, Patzert tracks a rapidly fading El Niño. "Sometimes these El Niños are pretty small and the impacts are really marginal," he says. "That's really what we saw this winter." Still, climatologists keep their eyes on the Pacific. The minute you call El Niño an el "no-show," he'll prove you wrong.
El Niño typically lasts nine to 12 months and peaks from December to April. We can expect an El Niño every two to seven years.
BACKGROUND: NASA satellite data indicates El Niño has returned to the tropical Pacific Ocean, noting a general warming of ocean temperatures and a rise in sea surface heights in the central and eastern Pacific along the equator. These are indicators of a developing El Niño. However, it is relatively weak and may not persist, since it is much less intense than the last major El Niño episode in 1997-1998. If the ocean waters continue to warm and spread eastward, the effect will strengthen, perhaps brining much-needed rainfall to the southwestern and southeastern United States this winter.
ABOUT EL NINO: El Niño is a cyclical warming of the ocean waters in the central and eastern tropical Pacific that generally occurs every three to seven years, usually around the holidays. It is associated with changes in air pressure and the movement of high-level winds, and can affect weather worldwide. In the United States, En Niño normally results in warmer-than-normal temperatures across the northern and western states. Wetter conditions result in the south, with dry weather across the Ohio Valley and Pacific Northwest. El Niño typically peaks during the winter months. It alternates with La Niña, the cooling of ocean waters in the same region of the Pacific.
IS IT RELATED TO GLOBAL WARMING? Scientists, don't discount the possibility, but there is very little information available linking El Niño to global warming. That's because little is known about the cause of El Niño, although scientists do have a good understanding of how the effect evolves once it begins. El Niños in different years can vary greatly in strength, indicating it is very sensitive to large-scale climate change. But we won't have a statistically significant sampling of such events for at least another 100 years
The American Meteorological Society contributed to the information contained in the TV portion of this report.