Ultraviolet light shone on cold winter conundrum
Richard Black By Richard Black Environment correspondent, BBC News
Recent cold winters that brought chaos to the UK and other places in northern Europe may have their roots in the Sun's varying ultraviolet emissions.
The latest satellite data shows the UV output is far more changeable than scientists had previously thought.
A UK scientific team now shows in Nature Geoscience journal how these changes lead to warmer winters in some places and colder winters in others.
The researchers emphasise there is no impact on global warming.
The Sun has recently been in a quiet phase of its regular 11-year cycle, which co-incided with three years in which the UK, along with other places in northern Europe and parts of the US, experienced cold conditions unusual in the recent record.
But unusually warm weather was felt both further south, around the Mediterranean Sea, and further north in Canada and Greenland.
"The key point is that this effect is a change in the circulation, moving air from one place to another, which is why some places get cold and others get warm," said Adam Scaife, one of the researchers on the paper, who heads the UK Met Office's Seasonal to Decadal Prediction team.
"It's a jigsaw puzzle, and when you average it up over the globe, there is no effect on global temperatures," he told BBC News........................http://www.bbc.co.uk/news/science-environment-15199065