This behaviour affects the peaks and valleys in the approximately 11-year solar cycle, sometimes amplifying and sometimes weakening the solar storms that can buffet Earth’s atmosphere.
The variations appear to be driven by changes in the bands of strong magnetic fields in each solar hemisphere. .
“What we’re looking at here is a massive driver of solar storms,” said Scott McIntosh, lead author of the new study and director of NCAR’s High Altitude Observatory.
“By better understanding how these activity bands form in the Sun and cause seasonal instabilities, there’s the potential to greatly improve forecasts of space weather events.”
These variations can be likened to regions on Earth that have two seasons, such as a rainy season and a dry season, McIntosh said.
The study is published this week in Nature Communications.
Bill Condie is a science journalist based in Adelaide, Australia.
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