DISTINCTIVE OZONE STRUCTURE IN THE HIGH-LATITUDE STRATOSPHERE - MEASUREMENTS BY THE MILLIMETER-WAVE ATMOSPHERIC SOUNDER

MAS (Millimeter-wave Atmospheric Sounder) observations from the shuttl e ATLAS spacelab pallet have revealed some little known (and unexplain ed) structure in stratospheric ozone mixing ratio profiles at sub-pola r latitudes, of both hemispheres. Qualitatively similar features are o bserved by UARS instruments. Another possibly related feature has been observed by ground-based remote sensing from the South Pole over an e xtended season. In all these cases, it seems likely that active photoc hemistry and highly structured horizontal and vertical transport play important roles. Some evidence of a similar feature is also present in a current 2-D photochemical model. This high latitude phenomenon is b oth an intriguing challenge for current 3-D models and potentially use ful test for validating remote sensing experiments.