Environment: Antarctic ozone hole closes early this year

Warmer stratosphere, active polar vortex help speed seasonal recovery

A graphic from the WMO shows the progression of the Antarctic ozone hole.

By Summit Voice

FRISCO — Relatively warm stratospheric temperatures helped limit the size of this year’s Antarctic ozone hole, which disappeared completely by Nov. 10, earlier than in recent years.

Using data gathered from ground stations and weather balloons, the World Meteorological Organization said the warmer temps at an elevation of about 20 kilometers limited the formation of polar stratospheric clouds which, through a chemical chain reaction between water, nitric acid and halogenated reservoir gases cause ozone loss. In this respect, the 2012 ozone hole was similar to the one in 2010, when a sudden stratospheric warming in July and August gave rise to a smaller amount of polar stratospheric clouds than usual.

The WMO also said the polar vortex — a large low-pressure system where high speed winds (polar jet) in the stratosphere circle the Antarctic continent — was also relatively perturbed and this led to ozone-rich air being transported in from lower latitudes.

The transport of ozone rich air was particularly noticable in the stratosphere at around 25 km altitude, above the region where most of the ozone loss takes place, which is typically in the 14-20 km height range. Ozone loss in the 14-20 km region took place at nearly the same extent as in recent years.

During the first half of August, the area increased more slowly than at the same time in many the recent years. Starting in mid-August, the increase was similar to 2011. From early September, the ozone hole area leveled off but increased a bit again after the middle of September. Starting early October, the ozone hole area dropped rapidly.

The Antarctic ozone hole is an annually recurring winter and spring phenomenon resulting from extremely low temperatures in the stratosphere and the presence of ozone-depleting substances. It typically reaches its maximum surface area during the second half of September and the maximum depth during the first half of October.

Despite a 25-year-old agreement that limits the production and use of ozone-destroying chemicals (the Montreal Protocol), stratospheric ozone in the Arctic and Antarctic regions, as well as globally, is no longer decreasing, but it has not yet started to recover either.

Ozone-destroying hemicals such as chorolflouorocarbons and halons have a long atmospheric lifetime, illustrating the delicate balance of the atmospheric system, which is currently being overloaded with heat-trapping greenhouse gases.

The ozone layer outside the Polar regions is projected to recover to its pre-1980 levels before the middle of this century. In contrast, the ozone layer over the Antarctic is expected to recover much later.


3 thoughts on “Environment: Antarctic ozone hole closes early this year

  1. So, based on limited measurements over just a few years before the ban on “ozone depleting chemicals”, after 25 years of not depleting the ozone by man, the ozone “hole” does what it does annually in spite of mankind. Just wondering, what it did 7000 years ago since what it did is only conjecture by “scientists” with a political agenda.

      1. Naivete towards the pure and innocent godless scientists is no excuse not to think. Reason and scientific inquiry seem to be forbidden in the new world order where we the plebes are to accept the pronouncements from on high as being the truth and nothing but the truth. All humans are subject to natural law, and that law says that all men are sinners. They all do what they believe to be in their interest not the good of others, so you can call names of those that think, you can spin conspiracy theories out of reasonable questioning, but you don’t change what is – is. Big oil, conspiracy, racism, and whatever other worn out liberal excuse not to think or question is getting old. Paul said in Galations 6 – that our freedom is not to pursue our fleshly lusts, but to pursue the obedience to Christ. I cherish my freedom and will not bow to the pursuit of pleasing the crowd that thoughtlessly follow whoever is foolish enough to think they know it all and leads them into the pit. I only ask people to question motives before they follow. That is conspiracy thinking to the new world order, of course. Don’t think, just follow. Good to know where you stand.

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