Estimation of Antarctic ozone loss from Ground-based total column measurements
1Université Versailles-Saint-Quentin, CNRS/INSU, UMR 8190 LATMOS-IPSL, 91371 Verrières Le Buisson, France
2UPMC Univ. Paris 06, CNRS/INSU, LATMOS-IPSL, 75005 Paris, France
3British Antarctic Survey, Cambridge, UK
4School of Earth and Environment, University of Leeds, UK
Abstract. The passive ozone method is used to estimate ozone loss from ground-based measurements in the Antarctic. A sensitivity study shows that the O3 loss can be estimated within an accuracy of ~4%. The method is then applied to the observations from Amundsen-Scott/South Pole, Arrival Heights, Belgrano, Concordia, Dumont d'Urville, Faraday, Halley, Marambio, Neumayer, Rothera, Syowa and Zhongshan for the diagnosis of ozone loss in the Antarctic. On average, the five-day running mean of the vortex averaged ozone column loss deduced from the ground-based stations shows about 53% in 2009, 59% in 2008, 55% in 2007, 56% in 2006 and 61% in 2005. The observed O3 loss and loss rates are in very good agreement with the satellite observations (Ozone Monitoring Instrument and Sciamachy) and are well reproduced by the model (Reprobus and SLIMCAT) calculations.
The historical ground-based total ozone measurements show that the depletion started in the late 1970s, reached a maximum in the early 1990s, stabilising afterwards at this level until present, with the exception of 2002, the year of an early vortex break-up. There is no indication of significant recovery yet.
At southern mid-latitudes, a total ozone reduction of 40–50% is observed at the newly installed station Rio Gallegos and 25–35% at Kerguelen in October–November of 2008–2009 and 2005–2009 (except 2008) respectively, and of 10–20% at Macquarie Island in July–August of 2006–2009. This illustrates the significance of measurements at the edges of Antarctica.