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British Antarctic Survey Ozone BulletinsSituation at 2009 December 30The 2009 ozone hole is over, with the continent having experiencing the final stratospheric spring warming. Ozone values across the continent are around 300 DU, and the summer circulation is established. Ozone values in surrounding areas are generally lower than over the continent The temperature of the ozone layer over Antarctica is at its summer maximum and is now far too warm for polar stratospheric clouds (PSCs) to exist. During the early winter, the polar vortex was often rather more elliptical than it was in 2008, and this lead to some early depletion in circumpolar regions as stratospheric clouds became exposed to sunlight. It reverted to a more circular circulation as winter progressed and this led to another relatively slow start to the growth of the ozone hole (as measured by NASA/SBUV2), with the "hole" not beginning until mid August. The vortex became more elliptical again in late August, with South Georgia being affected by the fringes of the ozone hole between September 2 and 6. The hole grew to reach an area of around 24 million square kilometres by mid September, and then lasted until the end of November, although the final remnants of the polar vertex lingered until towards the end of the month. From mid August to mid November it remained around the average area seen over the past decade. The tip of South America and South Georgia were affected by the fringes of the ozone hole from September 24 to September 30, from October 3 to October 7 and from November 8 to 25. South Georgia was affected on November 6. See the final situation report for last year for information on the 2008 - 2009 season. Notes: The Antarctic ozone hole is usually largest in early September and deepest in late September to early October. September 16 is world ozone day, and in 2009 the final UN Member State to ratify the Montreal Protocol signed up. 2007 was the International Year of the Ozone Layer. Prior to the formation of ozone holes, Antarctic ozone values were normally at their lowest in the autumn (ie March). http://www.antarctica.ac.uk/met/jds/ozone/Final ozone layer situation reportsThe BAS ozone web page is updated regularly, with the situation report from the final update of the season being archived.
BAS issues regular ozone bulletins. Issues available are:
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