Moon’s shadow causes winds to slow, alter direction, study says.
The inky shadows of solar eclipses can alter local weather on small scales, according to new analysis of a 1999 total eclipse.
Solar eclipses occur when the moon slips between Earth and the sun, causing a huge shadow to glide across our planet’s surface. (See pictures from a January 2011 solar eclipse.)
Meteorologists knew an eclipse could lower temperatures within this shadow by as much as 5 degrees Fahrenheit (3 degrees Celsius). But they couldn’t confirm anecdotal reports of changes in wind speed and direction linked to the astronomical events.
“This story goes back to 1901, when a guy named H. Helm Clayton thought he saw a change in the wind directions on account of the eclipse,” said atmospheric physicist Giles Harrison of the University of Reading in the U.K.
Clayton published a paper saying there was such a thing as an eclipse cyclone—”a cyclone of winds around the moon’s shadow,” Harrison said.
Ever since Clayton’s claim, anecdotal reports of eclipse-powered winds have piled up, but without convincing data to support the notion.
National Geographic has the full article
