The impact of the mixing properties within the Antarctic stratospheric vortex on ozone loss in spring

Am. Lee et al., The impact of the mixing properties within the Antarctic stratospheric vortex on ozone loss in spring, J GEO RES-A, 106(D3), 2001, pp. 3203-3211
Citations number
Categorie Soggetti
Earth Sciences
Year of publication
3203 - 3211
SICI code
Calculations of equivalent length from an artificial advected tracer provid e new insight into the isentropic transport processes occurring within the Antarctic stratospheric vortex. These calculations show two distinct region s of approximately equal area: a strongly mixed vortex core and a broad rin g of weakly mixed air extending out to the vortex boundary. This broad ring of vortex air remains isolated from the core between late winter and midsp ring. Satellite measurements of stratospheric H2O confirm that the isolatio n lasts until at least mid-October. A three-dimensional chemical transport model simulation of the Antarctic ozone hole quantifies the ozone loss with in this ring and demonstrates its isolation. In contrast to the vortex core , ozone loss in the weakly mixed broad ring is not complete. The reasons ar e twofold. First, warmer temperatures in the broad ring prevent continuous polar stratospheric cloud (PSC) formation and the associated chemical proce ssing (i.e., the conversion of unreactive chlorine into reactive forms). Se cond, the isolation prevents ozone-rich air from the broad ring mixing with chemically processed air from the vortex core. If the stratosphere continu es to cool, this will lead to increased PSC formation and more complete che mical processing in the broad ring. Despite the expected decline in halocar bons, sensitivity studies suggest that this mechanism will lead to enhanced ozone loss in the weakly mixed region, delaying the future recovery of the ozone hole.