Cold winters linked to sun’s activity
A team led by Mike Lockwood of the University of Reading compared levels
of solar activity with the Central England Temperature record (CET),
the world’s longest continuous instrumental temperature record. Their
results showed a strong link between low winter temperatures and reduced
solar activity.
There are a number of possible explanations for the link, but Lockwood’s team leans towards a meteorological phenomenon known as ‘blocking’, whereby the jet stream forms an ‘S’ shape over the northeastern Atlantic, causing the wind to fold back on itself. If the jet stream is blocked and pushed north, it leads to cold, dry easterly winds flowing over Europe, bringing a sharp drop in temperatures. Last winter’s cold weather was the result of just such a situation.
The sun’s output of ultraviolet radiation determines the heat of the stratosphere. This, in turn, drives winds in the troposphere, which is where the jet stream occurs. Hence a drop in the sun’s activity could feasibly change the behaviour of the jet stream.
The sun’s activity tends to increase quite slowly over a roughly 300-year period and then drop more quickly, over a period of about a century. The present decline began in around 1985, and hence is around halfway towards its minimum activity, suggesting that more cold winters could be on their way.
June 2010
There are a number of possible explanations for the link, but Lockwood’s team leans towards a meteorological phenomenon known as ‘blocking’, whereby the jet stream forms an ‘S’ shape over the northeastern Atlantic, causing the wind to fold back on itself. If the jet stream is blocked and pushed north, it leads to cold, dry easterly winds flowing over Europe, bringing a sharp drop in temperatures. Last winter’s cold weather was the result of just such a situation.
The sun’s output of ultraviolet radiation determines the heat of the stratosphere. This, in turn, drives winds in the troposphere, which is where the jet stream occurs. Hence a drop in the sun’s activity could feasibly change the behaviour of the jet stream.
The sun’s activity tends to increase quite slowly over a roughly 300-year period and then drop more quickly, over a period of about a century. The present decline began in around 1985, and hence is around halfway towards its minimum activity, suggesting that more cold winters could be on their way.
June 2010
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