October 20, 2006 3:35 PM PDT
Ozone hole over South Pole growing
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According to scientists from both NASA and the National Oceanic and Atmospheric Administration (NOAA), the ozone hole over Antarctica is getting wider and deeper.
The Ozone Monitoring Instrument on NASA's Aura satellite determined that the hole over the South Pole was 10.6 million square miles between September 21 and 30 of this year, according to a joint announcement from the two groups.
That is the largest average ever observed, according Paul Newman, a scientist with NASA's Goddard Space Flight Center in Greenbelt, Maryland. (The largest single day occurrence was 11.4 million square miles on Sept. 9, 2000.)
The ozone layer over Antarctica, according to the statement, was aggravated by high levels of chlorine chemicals about 12.4 miles from the Earth's surface. The data was based on observations made by the Aura in September, as well as natural weather fluctuations in the Antarctic stratosphere.
The ozone layer is also getting significantly thinner and patchy, according to NOAA scientists.
Dobson Units (DU), the measurement of ozone thickness, plunged from an average of 300 DU over the South Pole in mid-July to 93 DU on Oct. 9, according to measurements taken from NOAA's Earth System Research Laboratory. Some areas that were at 125 DU in July and August, measured a record low of 1.2 DU.
"These numbers mean the ozone is virtually gone in this layer of the atmosphere," said David Hofmann, director of the Global Monitoring Division at the NOAA Earth System Research Laboratory, in the statement.
The joint report noted that the ozone situation is not a complete surprise.
The 2006 World Meteorological Organization/United Nations Environment Programme Scientific Assessment of Ozone Depletion concluded that despite efforts made as part of the Montreal Protocol, an international agreement to reduce the world's ozone-depleting gases, the ozone layer will not completely recover from past pollution until 2065.
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