Heavy rain, flooding, and even outbreaks of bug-borne disease in East Africa may be linked to sunspots, scientists say.
The unusual finding is the result of a new study that found a correlation between peak sunspot activity and severe, mosquito-breeding rains in East Africa.
What drives the dynamic is not clear, said the study's lead author, J. Curt Stager of Paul Smith's College in New York.
The key factor is likely not the sunspots themselves but the slight brightening of the sun that goes along with them, he said.
This brightening isn't severe—only a fraction of a percent—but in the intense sunlight of the tropics, it may be enough to warm the oceans slightly, putting more moisture in the air, Stager said.
At the same time, the land may also warm up, causing the moist air to rise and producing more rain clouds.
"So you get a double-whammy amplifying effect from what would otherwise be a weak solar signal," Stager said.
The solar cycle, which runs in 11-year phases, is also known to affect winds in the upper atmosphere, he noted.
"That can affect the flow of air that makes it rain," Stager said. "So it could be little things that hit certain parts of the world just the right way.
"The basic story is that the rhythm has been steady for more than a hundred years," Stager said of the pattern his team observed.
"It hasn't skipped a beat. If it was just coincidence, it should have drifted off, but it's been right on."
Old Theory Revived
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