'Why Has an Ozone Hole Appeared over Antarctica When CFCs and Halons Are Released Mainly in the Northern Hemisphere?'

However, the reason we have a southern ozone hole instead of a northern one is not due to the amount of atmospheric pollution — it's due to temperature.

The stratosphere in the southern hemisphere — the layer of atmosphere where the ozone layer lies, 15 to 50 kilometres above the Earth's surface — is about five degrees Celsius colder than in the northern hemisphere.

"We get more ice in the stratosphere in the southern hemisphere, making the ozone-depleting chemicals more potent," Fraser says.

"This leads to that disparity between hemispheres as far as ozone [depletion] is concerned since it's not the level of chemicals that is driving them, but the ability of those chemicals to deplete ozone."

Chlorofluorocarbons (CFCs) are one type of ozone-depleting chemicals. They react with ultraviolet light to produce chlorine, which is then able to destroy ozone.

This chemical reaction that frees chlorine from CFCs takes place on the surface of tiny particles of ice in the stratosphere.

"The more ice there is in the stratosphere, the more ozone-destroying chlorine is liberated from CFCs," Fraser says.

http://www.abc.net.au/science/articles/2009/06/03/2588286.htm

It's because their is more ice in the statosphere in the southern hemisphere to facilitate the destruction of ozone. So even though there are less CFCs in the southern hemisphere they are more potent.

John_Taverner wrote on Dec 20^th, 2015 at 2:00pm:



It doesn't explain the transport of CFC's from the Northern Hemisphere to the Southern Hemisphere.

' Because of the lack of topography or land-ocean contrast to disturb the westerly flow at southern midlatitudes, little meridional transport takes place and the antarctic atmosphere is effectively isolated from lower latitudes.'

http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html

Daniel J. Jacob
Vasco McCoy Family Professor
of Atmospheric Chemistry
and Environmental Engineering
Harvard University

Looking at Interhemispheric exchanges

'    3. 4 Interhemispheric exchange

In this problem we use observations of the radioactive gas 85Kr to determine the characteristic time for exchange of air between the northern and southern hemispheres. We consider a 2-box model where each hemisphere is represented by a well-mixed box, with a rate constant k (yr -1 ) for mass exchange between the two hemispheres. Our goal is to derive the residence time t = 1/k of air in each hemisphere. '

http://acmg.seas.harvard.edu/people/faculty/djj/book/bookhwk3.html#76878

Ahh, back to the well mixed gases.