Solar changes help create cold northern winters

Solar changes help create cold northern winters

Fluctuations in ultraviolet light can set up frigid, snowy conditions

By Alexandra Witze
Web edition : Monday, October 10th, 2011

Harsh winters in the United States and northern Europe may partly be the result of changes in ultraviolet radiation coming from the sun.

A new climate simulation study shows how fluctuations in ultraviolet light linked to the sun’s 11-year activity cycle could change winter weather patterns across the Northern Hemisphere. The work appears online October 9 in Nature Geoscience.

“We hope this will open the door to improving ultralong-range predictions,” says co-author Adam Scaife, a climate modeler at the Met Office’s Hadley Centre in Exeter, England.

Scientists have long noted anecdotal links between low solar activity and cold European winters: Part of the Little Ice Age, which gripped the region between about 1550 and 1850, coincided with a record low number of sunspots, which are one measure of solar activity. But until now, Scaife says, no one had found a physical explanation for how subtle changes in radiation hitting the top of Earth’s atmosphere could translate to changes in weather patterns at the surface.

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