The Arctic tropopause fold.

Abstract

Analyses of research aircraft observations, satellite total columnar ozone retrievals and synoptic upper-air soundings are used to describe the structure of Arctic jetstreams and their associated frontal zones and tropopause folds. These analyses document the presence of major tropopause folding events within the Arctic that occur at the flanks of large-scale (about 2000km) polar vortices. One example shows a polar vortex and its associated tropopause fold and Arctic front that migrated from the high Canadian Arctic S into midlatitudes over central North America. The frigid cold-air outbreak associated with this migration was an important component in the record setting daily minimum temperatures that were recorded from the Great Lakes to S Florida. Total columnar ozone measurements from (TOMS) are shown to identify the location of polar vortices and the mesoscale (about 200km) ozone gradients at the flanks of these vortices, which coincide with regions of Arctic tropopause folding and associated stratopheric tropospheric exchange (ST) processes.-from Authors