ScienceDaily (Sep. 24, 2009) — El Niño, the periodic eastern Pacific phenomenon credited with shielding the United States and Caribbean from severe hurricane seasons, may be overshadowed by its brother in the central Pacific due to global warming, according to an article in the September 24 issue of the journal Nature.
"There are two El Niños, or flavors of El Niño," said Ben Kirtman, co-author of the study and professor of meteorology and physical oceanography at the University of Miami's Rosentstiel School of Marine and Atmospheric Science. "In addition to the eastern Pacific El Niño which we know and love, a second El Niño in the central Pacific is on the increase."
El Niño is a recurring warm water current along the equator in the Pacific Ocean that affects weather circulation patterns in the tropics. The eastern El Niño increases wind sheer in the Atlantic that may hamper the development of major hurricanes there. The central Pacific El Niño, near the International Dateline, has been blamed for worsening drought conditions in Australia and India as well as minimizing the effects of its beneficial brother to the east.
Article discusses computer models, and that recent weather patterns are consistent with the models.
"Currently, we are in the middle of a developing eastern Pacific El Niño event," said Kirtman, "which is part of why we're experiencing such a mild hurricane season in the Atlantic. We also anticipate the southern United States to have a fairly wet winter, and the northeast may be dry and warm."
Kirtman expects the current El Niño event to end next spring, perhaps followed by a La Niña, which he expects may bode for a more intense Atlantic hurricane season in 2010.