October 11, 2011
Drop In Radiation Can Trigger Cold Winters
According to a new study, a drop in the sun's radiation can trigger unusually cold winters in parts of North America and Europe.
The scientists said this finding could improve long-range forecasts and help countries prepare for blizzards.
Previously, researchers were just able to see a weak link between solar activity and winter weather. However, the new study used satellite measurements from NASA's Solar Radiation and Climate Experiment (SORCE) to reveal that differences in UV light reaching the Earth during the 11-year cycle are larger than previously thought.
The satellite, which launched in 2003, helped to take the first-ever measurement of the solar radiation across the entire UV spectrum.
The sun has an 11-year cycle radiation on the surface, during which it reaches a peak and then falls.
The researchers focused on data from the recent solar minimum during 2008 and 2010, which was a period that saw unusual calm for the sun and intense winters in the U.S. and parts of Europe.
The scientists found that a reduction in ultraviolet (UV) radiation from the sun can affect high-altitude wind patterns in the Northern Hemisphere, which triggers cold winters.
When solar activity is higher than usual, the opposite can take place and bring warm air and milder winters.
"What we're seeing is UV levels affecting the distribution of air masses around the Atlantic basin," lead author Sarah Ineson, from the U.K. Met Office, said in a press release. "This causes a redistribution of heat, so while Europe and the US may be cooler, Canada and the Mediterranean will be warmer, and there is little direct impact on global temperatures."
The study was published in the journal Nature Geoscience.
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