Weather in Space

Sunspots and Solar Activity

How do sunspots affect weather?

While scientists still debate how important or significant sunspot activity is on our weather and climate, there are some theories. In the short term, solar flares and winds do not influence weather to any significant extent because the magnetosphere and upper atmosphere are more than capable of absorbing their energy. Over the long term, however, there could be consequences if the Sun experienced a prolonged or permanent change in activity.

Fluctuations in solar activity typically occur in the ultraviolet wavelengths, and UV radiation is known to affect the Earth’s upper atmosphere. Astronomers and some meteorologists speculate that X-rays, too, resulting from sunspots and flares could, over time, change the amount of nitric oxide (NO) in the upper atmosphere, and this would have an effect on the ozone. Sunspot activity can result in more cosmic rays penetrating the atmosphere, which, in turn, spur on cloud formation and increase precipitation.

More recently, there have been theories that significant decreases in solar activity predict oncoming ice ages on our planet. For example, during the Little Ice Age that lasted from the fifteenth through the eighteenth centuries (a period including the Maunder Minimum), sunspot activity was at a low point. Other minimums (the Dalton Minimum [1790—1820] and Spörer Minimum [1420–1530]) also coincide with colder weather.

A photo taken at the Dryden Flight Research Center in Edwards, California, took advantage of a smoky sky to reveal sun spots. (photo by Tom Tschida courtesy NASA)

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