Decadal evolution of the Antarctic ozone hole

摘要: Ozone column amounts obtained by the total ozone mapping spectrometer (TOMS) in southern polar region are analyzed during late austral winter and spring (days 240–300) for 1980–1991 using area-mapping techniques area-weighted vortex averages. The here is defined −50 PVU (1 = 1.0 × 10^(−6) K kg^(−1) m^2 s^(−1)) contour on 500 isentropic surface. principal results are: (1) there a distinct change after 1985 vortex-averaged depletion rate September October, period of maximum loss, (2) August (day 240) has dropped 70 Dobson units (DU) decade due to loss dark dilution effect. mean between day 240 minimum about 1 DU d^(−1) at beginning decade, increasing 1.8 1985, then apparently saturating thereafter. vortex-average October declined 11.3 yr^(−1) (3.8%) from 1980 1987 (90 over 8 years) smaller 2 (0.9%) 1991 (10 5 years, excluding anomalous year 1988). We interpret year-to-year trend earlier part as rise anthropogenic chlorine atmosphere. slower end indicates saturation interior, that mid-1980s were already sufficiently high deplete most air within isolated regions lower-stratospheric vortex. In subsequent increases stratospheric may have enhanced wintertime chemical south even before major losses Antarctic spring.