Solar Eclipses Can Change Weather on Earth
â€” National Geographic News
The study of solar eclipse-induced wind changes was published March 14 in the journal Proceedings of the Royal Society A.
Children gaze at a partial solar eclipse over Manila Bay, the Philippines, in 2009.
Photograph by Gil Nartea, AFP/Getty Images
Published March 28, 2012
The inky shadows of solar eclipses can alter local weather on small scales, according to new analysis of a 1999 total 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 cycloneâ€”"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.
Eclipse's Weird Winds
Looking to put the issue to rest, Harrison and colleague Suzanne Gray, an atmospheric scientist also at the University of Reading, gathered weather data from the path of an August 1999 eclipse.
That eclipse's shadow sliced across Europe, including Devon and Cornwall in the U.K.
During the event Harrison was under cloudy, rainy skiesâ€”"the wrong place at the right time" for noticing slight changes in weather patterns. But onlookers elsewhere in the country reported feeling an odd change in wind direction when the eclipse occurred.
Fortunately, stations across Europe recorded a wealth of weather data under clearer skies.
Gray and Harrison used the pre-eclipse conditions and computer modeling to create a forecast for that day that did not account for the eclipse's shadow. The researchers then compared their results to actual weather data logged during and after the event.
The comparison showed a significant decrease in wind speed of about 1.6 miles (2.5 kilometers) an hour. Winds also blew 20 degrees more southerly in the shadowed regions.
"When the eclipse influences temperature, it seems to also cause the wind to drop and change direction. This is perhaps what people have remarked about," Harrison said. >>>>