THE ANOMALOUS ARCTIC LOWER STRATOSPHERIC POLAR VORTEX OF 1992-1993

Potential vorticity (PV) gradients defining the lower stratospheric vo rtex during the 1992-1993 winter were anomalously strong and persisten t compared to those during the last 16 Arctic winters. For almost-equa l-to3 months PV gradients were closer to typical Antarctic values than to most Arctic values. Air motion diagnostics computed for 3-dimensio nal air parcel trajectories confirm that the 1992-1993 Arctic lower st ratospheric vortex was substantially more isolated than is typical. Su ch isolation will delay and reduce the export of the higher ozone typi cal of the winter lower stratospheric vortex to mid-latitudes. This ma y have contributed to the record-low total ozone amounts observed in n orthern mid-latitudes in 1993.