| A three-dimensional chemical transport model incorporating chemistry using parameterized production-loss rates, and driven by assimilated winds, is used to isolate the effects of the Antarctic ozone hole (AOH) on southern midlatitudes. Simulations with and without polar stratospheric cloud (PSC) chemistry are performed for the years 1997--2000. It is found that, averaged over a period between 1997--2000, a ∼3.7% decline in the midlatitudes column ozone can be attributed to the PSC-initiated polar ozone losses. The springtime midlatitude ozone loss resulting from the polar decline is greatest (-4.9%) in 2000 and smallest (-2.5%) in 1999. The observed difference in the year-to-year AOH midlatitude contribution depends upon the interannual variations in the strength of extratropical planetary wave numbers 1 and 2. While wave 1 is more important in polar-midlatitude transport during September--October, wave 2 exhibits a greater significance in November--December. |
