HR: 11:20h
AN: U42A-05    [Abstracts]
TI: Solar Influence On ENSO And The Tropics?
AU: * Cane, M A
EM: mcane@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Emile-Geay, J B
EM: julieneg@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Seager, R
EM: rich@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Clement, A C
EM: aclement@rsmas.miami.edu
AF: Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 United States
AU: Mann, M E
EM: mann@virginia.edu
AF: University of Virginia, Dept. of Environmental Sciences, 353 Clark Hall, Charlottesville, VA 22903 United States
AB: Abstract We consider the possibility that variations in solar irradiance have a significant impact on the climate of the tropics, including the El Ni¤o-Southern Oscillation (ENSO) cycle. It is well known that ENSO has a large impact on regional climates worldwide, with subsequent impacts on ecosystems and society. Very recent work (Schubert et al. 2004; Seager et al. 2004) has shown that a prime cause of the Dust Bowl droughts of the 1930s is a La Ni¤a-like pattern of decadal mean sea surface temperature anomalies in the Pacific. These anomalies were very small amplitude (<0.5øC everywhere). Decadal anomalies of similar size in the tropical West Pacific and Indian Oceans have been shown to impact the North Atlantic sector (Hoerling et al., 2001); other small amplitude anomalies throughout the tropical Indian and Pacific Oceans appear to be responsible for widespread midlatitude droughts from 1998-2002 (Hoerling and Kumar, 2003). Our recent work (Mann et al. 2004) has shown that coupled ocean-atmosphere interactions in the tropical Pacific generate a significant response to solar and volcanic radiative forcing over the past 1000 years. Here we focus on solar variations. While they are unlikely to have much effect on individual El Ni¤o-Southern Oscillation (ENSO) events, they may influence characteristics of the ENSO cycle by changing the background state. Shifts in the ENSO cycle or the background state of the tropical Pacific could help explain persistent climate anomalies around the world over the last 1000 years. Noise or chaos internal to the climate system clearly is responsible for much of the decade to decade variation in the ENSO cycle, which has caused droughts such as those of the 1930s. But does solar variability also play a role? What is the impact of solar variability on the tropical climate in general, on timescales from decades to millennia?
DE: 3344 Paleoclimatology
DE: 4522 El Ni¤o
SC: Union [U]
MN: 2004 AGU Fall Meeting