Ozone hole over Antarctic 2nd smallest in 2 decades
Published on Oct 25, 2012 8:39 AM
WASHINGTON (AFP) - The seasonal hole in the ozone layer above the Antarctic this year was the second smallest in two decades, but still covered an area roughly the size of North America, United States experts said on Wednesday.
The average size of the Earth's protective shield was 17.9 million sq km, according to satellite measurements by the US National Oceanic and Atmospheric Administration and the space agency, the National Aeronautics and Space Administration (Nasa).
"It happened to be a bit warmer this year high in the atmosphere above Antarctica, and that meant we didn't see quite as much ozone depletion as we saw last year, when it was colder," said Jim Butler of NOAA's Earth System Research Laboratory in the Colorado city of Boulder.
The Antarctic ozone hole, which forms in September and October, reached its largest size for the season - 13.2 million sq km, roughly the combined area of the United States, Mexico and Canada - on Sept 22, NOAA said.
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