Antarctic ozone depletion

It now appears that both the extreme magnitude and geographic limitations of the Antarctic ozone depletion are due to meteorologic patterns peculiar to the South Polar regions. The large decrease beyond the small reduction in the rest of the stratosphere apparently involves the circulation of the polar vortex, a complex interaction of Cl with oxides of nitrogen, their physical trapping in extremely cold (T < — 80°C) clouds and preferential removal of some species by precipitation. 

Leu, M.-T., Heterogeneous Reactions of N20 with H20 and HCI on Ice Surfaces Implications for Antarctic Ozone Depletion, Geophys. Res. Lett, 15, 853-854 (3988b). 

Tolbert, M. A., M. J. Rossi, and D. M. Golden, Antarctic Ozone Depletion Chemistry Reactions of N205 with H20 and HCI on Ice Surfaces, Science, 240, 1018-1021 (1988b). 

It is clear from the data presented in this chapter that the effects of control strategies developed for CFCs and halons are already measurable. Although loss of stratospheric ozone with accompanying increases in ultraviolet radiation in some locations have clearly occurred, the tropospheric concentrations of CFCs are not increasing nearly as fast as in the past. Indeed, the concentrations of CFC-11 and CFC-113 appear to have peaked and have started to decline. The equivalent effective stratospheric chlorine concentrations are predicted to have peaked about 1997 and to return to levels found around 1980 at about the year 2050 (World Meteorological Organization, 1995). The significance of the 1980 level is that these levels resulted in detectable Antarctic ozone depletion. 

Booth C.R, and S. Madronich, Radiation amplification factors Improved formulation accounts for large increases in ultraviolet radiation associated with Antarctic ozone depletion, Antartcic Research Series, 62,39-42,1994. 

Roscoe, H.K., Jones, A.E. and Lee, A.M., (1997) Midwinter Start to Antarctic Ozone Depletion Evidence from Observations and Models, Science, VOL. 278, 93-96... 

Solomon, S. (1990) Progress towards a quantitative understanding of Antarctic ozone depletion, Nature 347,347-354. 

D. Karentz, H.J. Spero (1995). Response of a natural Phaeocystis population to ambient fluctuations of UVB radiation caused by Antarctic ozone depletion. J. Plankton Res., 17,1771-1789. 

Observations of PSCs, low NO2 amounts in polar regions (Figure 6.12), enhanced polar HNO3 (Murcray et al, 1975 Williams et al, 1982) and the vertical profile of the ozone depletion based upon the Japanese measurements (Chubachi, 1984) were cited in support of heterogeneous chemistry as the primary process initiating Antarctic ozone depletion. Such a mechanism would be most effective in the Antarctic due to colder temperatures and greater PSC frequencies there than in the corresponding seasons in the Arctic (McCormick et al, 1982), a point discussed further below. 

Atkinson, R.J., W.A. Matthews, P.A. Newman, and R.A. Plumb, Evidence of midlatitude impact of Antarctic ozone depletion. Nature 340, 290, 1989. 

Roscoe, H.K., A.E. Jones, and A.M. Lee, Midwinter start to Antarctic ozone depletion Evidence from observations and models. Science 278, 93, 1997. 

McGrath, M. P., Clemitshaw, K. C., Rowland, F. S., and Hehre, W. J. (1990) Structures, relative stabilities, and vibrational spectra of isomers of CI2O2 The role of chlorine oxide dimer in Antarctic ozone depleting mechanisms, J. Phys. Chem. 94, 6126-6132. 

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