“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,” says this article in BBC News.
These revelations come from the SOlar Radiation and Climate Experiment (SORCE), a NASA satellite launched in 2003.
The satellite’s Spectral Irradiance Monitor (SIM) records variations in the Sun’s UV emissions during a sunspot cycle. These emissions are about five times larger than previously believed.
When researchers plugged SIM’s measurements into the Met Office Hadley Centre climate computer model, the results reinforced the idea that the UV variations do indeed affect winter weather, and showed how the process might work.
“UV is absorbed in the upper atmosphere by ozone. In the quiet part of the solar cycle when there is less UV to absorb, the stratosphere is relatively cooler.”
This changes wind speeds, including the jet stream, and re-distributes temperatures around the globe.
In addition to the 11-year sunspot cycle, the Sun’s output also varies on longer timescales.
The Sun’s intensity has increased since the 1600s when sunspots almost disappeared for decades, a period known as the Maunder Minimum.
The Maunder Minimum coincided with the Little Ice Age, when winter weather overall grew colder in parts of Europe.
“Mike Lockwood of the UK’s Reading University, who also studies possible associations between solar changes and climate, suggested that if the Sun’s ultraviolet output varies as much on long timescales as it does across the solar cycle, that could provide the connection between the Maunder Minimum and the temperature changes.”
Note: The researchers insist that “there is no impact on global warming.” It simply “re-distributes temperatures,” leading to warmer winters in some places and colder winters in others.
I find that hard to believe. I think we’ll eventually learn that temperatures declined around the globe during the Little Ice Age.
I’ve simplified this considerably, so you’ll probably want to see the entire article:
Thanks to Icewoman, Mick Russell and Steve Foster for this link