DYNAMICAL MODELING OF WINTERTIME LIDAR OBSERVATIONS IN THE ARCTIC - OZONE LAMINAE AND OZONE DEPLETION

A series of lower stratospheric ozone profiles taken by a lidar during February 1995 in northern Norway are examined. The instrument locatio n allowed continuous monitoring of rapidly evolving layered ozone stru ctures, or laminae, near the polar vortex edge. Observations under the vortex edge revealed laminae extending up to 20 Irm. Moreover, when t he lidar was sampling vortex air, a thicker layer, characterized by un usually low mixing ratios, was also observed, thereby confirming satel lite observations of Arctic ozone depletion during the winter 1994/95. To unravel the respective role of dynamics and chemistry in generatin g these ozone-depleted layers requires better understanding of trace c onstituent lamination and filamentation through numerical modelling. H igh-resolution modelled realistic transport of idealized tracers and s atellite-derived ozone on many isentropes is therefore used to reconst ruct fine-scale three-dimensional tracer fields. Tilted tracer or ozon e sheets, peeled off near the vortex edge, lead to the formation of la minae in profiles. The model shows remarkable success in reproducing l aminae intensification, thickening and lofting, analogous to the ones observed by the lidar over the course of a few hours.