Storm track signature in total ozone during Northern Hemisphere winter

Abstract

Total ozone has long been known to correlate with tropospheric synoptic eddy activity, with low total ozone associated with anticyclonic conditions. Synoptic eddy activity is particularly intense in the storm track regions over the North Atlantic and Pacific oceans during boreal winter. An Eulerian diagnostic was introduced by Blackmon et al. [1977] to investigate storm tracks, based on band-pass filtering the 500 mb geopotential height for synoptic time scales. Wintertime daily satellite observations of total ozone have been analyzed using a similar Eulerian approach. Storm track signatures in total ozone, referred to as ozone tracks, can be discerned. However, the North Atlantic ozone track is stronger than the North Pacific one, and this asymmetry is in part due to intense ozone mini-hole events in the Atlantic sector, causing extreme total ozone variations. During winter 1996/97, this asymmetry was particularly marked. Furthermore, the Atlantic storm track and the corresponding ozone track were confined to the western Atlantic, due to persistent anticyclonic conditions over western Europe in late winter and spring. Several intense mini-hole events occurred in the Atlantic sector, with the strongest event in mid-March 1997.