Start Date/Time: Monday, May 23, 2005, 7:00 PM
Location: Kane Hall, UW Campus
Lecture by Michael McPhaden Senior Research Scientist at NOAA/Pacific Marine Environmental Laboratory and Affiliate Professor of Oceanography at UW. Powerpoint Slides
Every few years, unusually warm ocean temperatures develop in the tropical Pacific in association with a pronounced weakening of the trade winds. We refer to these conditions, which typically last 12-18 months, as El Niño. Once thought of as confined to the coast of Ecuador and Peru, we now know that warm ocean temperatures linked to El Niño stretch westward nearly all the way across the Pacific basin. El Niño’s reach in the atmosphere is even greater, extending to the far corners of the planet via atmospheric “teleconnections” (shifts in atmospheric circulation forced from the tropical Pacific). Atmospheric teleconnections alter normal patterns of weather variability and increase the probability of droughts, floods, wildfires, and severe storms in many parts of the globe. In the Pacific Northwest, El Niño typically leads to unusually warm winter air temperatures, reduced winter snowpack, and elevated coastal ocean temperatures. El Niño’s societal and economic consequences for both the Northwest and the globe are far ranging because of its effects on agriculture, power generation, commercial fisheries, financial markets, public health, transportation, recreation, and many other spheres of human activity. As one yardstick of impact, the 1997-98 El Niño (by some measures the strongest of the 20th century) caused $36 billion in economic losses and claimed 23,000 lives worldwide.
This presentation will review our current understanding of El Niño and its cold counterpart, La Niña. Recent advances in our ability to observe and predict El Niño and La Niña will also be discussed. Finally, we will address the question of whether El Niño may be changing either as a result of natural variations in the climate system or as a result of global warming.
For those interested in viewing the lecture, it is available on VHS from the Office of the Program on Climate Change (firstname.lastname@example.org 206-543-6521).