A tour of the ozone hole - PowerPoint - PowerPoint

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					            The Ozone Hole
             Tejas Patel
             PEP
             Universität Bremen




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Contents
1.    History of Ozone Loss
2.    Chemical processes in Ozone depletion
3.    Regions of Interest
4.    Polar Vortex
5.    Ozone hole only at poles???
6.    Anthropogenic Impacts on Ozone hole
7.    Health Consequences
8.    Summary
9.    Referances

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History of Ozone Loss

  Loss of ozone in the lower stratosphere over
   Antarctica was first noticed in the 1970s by
   British Antarctic Survey (BAS).




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            Vertical profile of ozone




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Chemical processes in Ozone depletion

• Chlorine, bromine – from human activities
• Chlorine carriers – hydrochloric acid, chlorine
  nitrate
• Other compounds – nitric acid, dinitrogen pent oxide
• PSC
• Denoxification – slows removal ClO



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Regions of Interest




Ref:http://www.solcomhouse.com/akjrctic.gif




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            The Antarctic polar vortex




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Vortex explanation

• Antarctic stratosphere cools
• descends closer to the surface
• Coriolis effect - sets up strong westerly
  circulation
• temperatures - lower stratosphere cool < -
  80C  PCS’s


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Ozone loss over Antarctica

•   Mostly in the lower stratosphere
•   persists two months
•   nearly all the ozone is depleted
•   area the size of Antarctica
•   most pronounced in spring/October



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Monthly averages for October




    Ref:http://www.atm.ch.cam.ac.uk/tour/tour_images/oct_ozone.gif




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Is the ozone loss only in Antarctica?

• Arctic – ‘low ozone event’
• Arctic atmosphere, as result of the eruption
  of Mt Pinatubo
• European ozone hole - heavily populated
  northern mid-latitudes (30-60N) – formation
  smaller, much slower



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Why is the loss more dramatic at the
poles?
•   Polar vortex – winter polar night
•   Polar stratospheric clouds (-80C)
•   nitric acid trihydrate
•   Chemical reactions
     • occur on surface PSC’s
     • Occur very fast



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What do these clouds look like?




http://www.abc.net.au/science/news/img/environment/nacreous020806.jpg


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      Impact of CFC’s




One chlorine atom destroys one thousand ozone
molecules
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Health Consequences

• Skin cancers, sunburn, eye damage
• estimated 10 % reduction ozone layer  25
  % increase non-melanoma skin cancer -
  temperate latitudes by 2050
• Suppress immune system
• DNA mutation of existing disease bacteria
  and viruses

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Summary
• Massive Ozone loss is in spring time in Antartic
  stratosphere due to anthropogenic halogens.
• Difference between Artic and Antartic stratosphere is
  temperature.
• Most of the features of polar ozone depletion is now
  understood but still number of issues remain to be
  unsolved.




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   A Little Spaß with Science




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Thank You for being patient !!!!

Questions???
Comments!!!!!!
Suggestions………………




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References

• Ref:http://www.solcomhouse.com/akjrctic.gif

• Ref:http://www.atm.ch.cam.ac.uk/tour/tour_images/oct_ozon
  e.gif

• www.atm.ch.cam.ac.uk/tour

• http://ozonewatch.gsfc.nasa.gov/facts/hole.html

• http://www.theozonehole.com/




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