Physics and chemistry of stratospheric ozone and interactions with climate change

Jayanarayanan Kuttippurath 1
1 STRATO - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
Abstract : Ozone is one of the key constituents in the atmosphere, although present only in trace amounts. The stratospheric ozone plays a pivotal role in regulating the incidence of harmful ultra-violet radiation (400- 100 nm) and radiative balance of the earth, and thus influences the global climate. This thesis deals with the spatial, temporal and vertical evolution of polar stratospheric ozone and its interactions with climate change over 1979-2012, with an emphasis on the winters of 2000s. Analysis of the dynamical situation in the Arctic winters reveals that there is an increase in the occurrence of major warmings (MWs) in recent years (1998/1999-2009/2010), as there were 13MWs in the 12 winters (⇠11 MWs/decade), although the long-term average (1957/1958-2009/2010) of the frequency stays around its historical value (⇠7MWs/decade). A study of the chemical ozone loss in the past 17 winters (1993/1994-2009/2010) suggests that the loss is inversely proportional to the intensity and timing of MWs in each winter, where early (December-January) MWs lead to limited loss. This high frequency of the MWs has significant implications for stratospheric ozone trends and hence, the Arctic and global climate. A detailed assessment of the Arctic winters 1996/1997 and 2002/2003-2010/2011 shows that the winter 2002/2003 had a MW and three minor warmings. However, the winter still had a cumulative ozone loss of ⇠1.5ppmv at 450-500K or 65DU over 400-550K by the end of March, apart from the record loss of ⇠0.7ppmv in December-January, as no other winter had such a large loss during the early winter over 1988/1989-2010/2011. In contrast, the largest ozone loss ever observed was in 2010/2011, about 2.5 ppmv at 400-550K or 140DU over 350-550K. Our study shows that the loss in 2010/2011 was close to that found in some Antarctic winters, for the first time in the observed history. The prolonged strong chlorine activation and denitrification during the winter triggered this record loss. The loss in other winters was between 0.7 and 1.6 ppmv at around 475 K or 40 and 115 DU over 350-550 K, in which the smallest loss was estimated in the warm winter 2005/2006. In order to make a long-term ozone loss time series for Antarctica, a method is introduced and applied to ground-based and space-borne total column ozone observations for the 1989-2012 period. The vortex- averaged ozone loss in the Antarctic is shown to be about 33-50% during 1989-1992 in agreement with the increase in halogens during that period, and then stayed at around 48% due to saturation of the loss. The loss in warmer winters (e.g. 2002 and 2004) is slightly smaller (37-46%) and the loss in very cold winters (e.g. 2003 and 2006) is relatively larger (52-55%). The maximum loss in the Antarctic is observed from mid-September to mid-October, and the peak loss rate is found in the August-early September period, with an average of about 0.5%/day. Furthermore, analysis with high resolution ozone profile measurements and simulations for the Antarctic winters 2004-2010 also showed the largest ozone loss in the colder winters of 2005 and 2006 with about 3.5 ppmv at 450-550 K or around 170 DU over 350-850 K, and the smallest loss in the warmer winters of 2004 and 2010 with about 2.5 ppmv at 450-550 K or around 140 DU over 350-850 K. The peak ozone loss altitude in Antarctica is around 500 K. However, the very cold winters show a higher and warmer winters show a lower shift in the peak loss altitudes (about 25 K), exhibiting a clear distinction between various winters in terms of the altitude of maximum loss. The study further indicates that the comparatively smaller Antarctic ozone loss and ozone holes in the recent winters (2004-2010) were due to the effect of a number of minor warmings during the period.
Document type :
Habilitation à diriger des recherches
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Submitted on : Wednesday, December 18, 2013 - 4:26:54 PM
Last modification on : Friday, January 10, 2020 - 3:42:30 PM
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  • HAL Id : tel-00920539, version 1

Citation

Jayanarayanan Kuttippurath. Physics and chemistry of stratospheric ozone and interactions with climate change. Atmospheric and Oceanic Physics [physics.ao-ph]. Université Pierre et Marie Curie - Paris VI, 2013. ⟨tel-00920539⟩

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