mercredi 6 mai 2015

Big Ozone Holes Headed For Extinction By 2040









NASA - EOS AURA Mission patch.

May 6, 2015

The next three decades will see an end of the era of big ozone holes. In a new study, scientists from NASA Goddard Space Flight Center say that the ozone hole will be consistently smaller than 12 million square miles by the year 2040.

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Big Ozone Holes Headed For Extinction By 2040

Ozone-depleting chemicals in the atmosphere cause an ozone hole to form over Antarctica during the winter months in the Southern Hemisphere. Since the Montreal Protocol agreement in 1987, emissions have been regulated and chemical levels have been declining.

However, the ozone hole has still remained bigger than 12 million square miles since the early 1990s, with exact sizes varying from year to year. The size of the ozone hole varies due to both temperature and levels of ozone-depleting chemicals in the atmosphere.

Artist's concept of the Aura spacecraft. Image Credit: NASA

In order to get a more accurate picture of the future size of the ozone hole, scientists used NASA’s AURA satellite to determine how much the levels of these chemicals in the atmosphere varied each year. With this new knowledge, scientists can confidently say that the ozone hole will be consistently smaller than 12 million square miles by the year 2040.

Scientists will continue to use satellites to monitor the recovery of the ozone hole and they hope to see its full recovery by the end of the century. Research: Inorganic chlorine variability in the Antarctic vortex and implications for ozone recovery.

Related links:

Journal: Geophysical Research: Atmospheres,  December 18, 2014. Link to paper: http://onlinelibrary.wiley.com/doi/10.1002/2014JD022295/abstract

For more information about AURA mission, visit: http://aura.gsfc.nasa.gov/ and http://www.nasa.gov/mission_pages/aura/main/index.html

Image (mentioned), Video, Text, Credits: NASA/Goddard Space Flight Center.

Greetings, Orbiter.ch

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