Recovery and regressionAntarctic ozone hole should start healing, while Arctic hole getting worsePosted October 14, 2011
Researchers at the National Oceanic and Atmospheric Administration (NOAA) That estimate is based on a new analysis of 25 years of data collected by NOAA scientists and colleagues at the Atmospheric Research Observatory (ARO) The research team — led by Birgit Hassler of NOAA’s Earth System Research Laboratory The ozone layer in the Earth’s stratosphere, between about 10 and 30 kilometers above the ground, helps shield the planet from harmful ultraviolet radiation. Human-produced compounds known as chlorofluorocarbons, or CFCs, release ozone-destroying chemicals into the atmosphere that are responsible for the depletion. ![]() Photo Credit: NASA
NASA images show the Arctic in 2010, at left, along with the severe ozone depletion, on right, in 2011.
Extreme cold, ice cloud formation in the stratosphere, and a pattern of rapidly circulating air, called the polar vortex, make the ozone layer over Antarctica much more vulnerable to CFC-destruction than almost anywhere else on the planet. Scientists first discovered the hole in 1985. An international treaty, known as the Montreal Protocol NOAA scientists at ARO launch balloons to measure ozone vertically at least once a week year-round at the South Pole, and more frequently in the austral spring when the polar vortex forms. [See previous article: Fresh air.] “This is not a total recovery. This will just be the first time that we can see the effects [of the ban],” Hassler told Boulder’s The Daily Camera newspaper in an interview. But all is not good news for ozone recovery in the Earth’s atmosphere. A NASA-led The amount of ozone destroyed in the Arctic in 2011 was comparable to that seen in some years in the Antarctic, according to the Nature paper. The process of ozone loss is similar in the polar regions, though warmer stratospheric conditions in the Arctic generally limit the extent of ozone depletion. Although the total amount of Arctic ozone measured was much more than twice that typically seen in an Antarctic spring, the amount destroyed was comparable to that in some previous Antarctic ozone holes, according to a press release |