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Ozone hole over Antarctic 2nd smallest in 2 decades

Published on Oct 25, 2012 8:39 AM
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A false-colour view of total ozone over the Antarctic pole is seen in this Nasa handout image released on Oct 24, 2012. The purple and blue colours are where there is the least ozone, and the yellows and reds are where there is more ozone. The average area covered by the Antarctic ozone hole this year was the second smallest in the last 20 years, according to data from Nasa and National Oceanic and Atmospheric Administration (NOAA) satellites. Scientists attribute the change to warmer temperatures in the Antarctic lower stratosphere. The ozone hole reached its maximum size on Sept 22, covering 21.2 million sq km, or the area of the United States, Canada and Mexico combined.-- PHOTO: REUTERS/NASA/HANDOUT

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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