http://www.nature.com/news/2009/090827/full/news.2009.869.html
Sunspots stir oceans
Variations in the Sun's brightness may have a big role in Pacific precipitation.
Computer simulations are showing how tiny variations in the Sun's brightness can have a big influence on weather above the Pacific Ocean. The simulations match observations that show precipitation in the eastern Pacific varies with the Sun's brightness over an 11-year cycle. However, the model does not indicate a relationship between solar activity and the rise in global temperature over the past century.
"This is not a global warming thing," says Gerald Meehl, a modeller at the National Center for Atmospheric Research in Boulder, Colorado, and first author of the study. "But it does indicate that the Sun has a measurable impact on Earth's climate." The research is published this week in the journal Science1.
Link to article in science
Amplifying the Pacific Climate System Response to a Small 11-Year Solar Cycle Forcing
Gerald A. Meehl,1,*Julie M. Arblaster,1,2Katja Matthes,3,4Fabrizio Sassi,5Harry van Loon1,6One of the mysteries regarding Earth’s climate system response to variations in solar output is how the relatively small fluctuations of the 11-year solar cycle can produce the magnitude of the observed climate signals in the tropical Pacific associated with such solar variability. Two mechanisms, the top-down stratospheric response of ozone to fluctuations of shortwave solar forcing and the bottom-up coupled ocean-atmosphere surface response, are included in versions of three global climate models, with either mechanism acting alone or both acting together. We show that the two mechanisms act together to enhance the climatological off-equatorial tropical precipitation maxima in the Pacific, lower the eastern equatorial Pacific sea surface temperatures during peaks in the 11-year solar cycle, and reduce low-latitude clouds to amplify the solar forcing at the surface.
(full text available on request)
