USE OF STRATOSPHERIC AEROSOL PROPERTIES AS DIAGNOSTICS OF ANTARCTIC VORTEX PROCESSES

Physical properties of the stratospheric aerosol population are inferr ed from cloud-free SAGE II multiwavelength extinction measurements in the Antarctic during late summer (February/March) and spring (Septembe r/October, November). Seasonal changes in these properties are used to infer physical processes occurring in the Antarctic stratosphere over the course of the winter. The analysis suggests that the apparent spr ingtime cleansing of the Antarctic stratosphere is the result of aeros ol, redistribution through subsidence of the polar vortex air mass and sedimentation of large polar stratospheric cloud particles. The analy sis also suggests that vortex processes are responsible for a signific ant downward transport of aerosol through the tropopause.