Signature of the North Atlantic Oscillation and Other Climate Patterns on Stratospheric Ozone

The primary modes of wintertime variability, such as the North Atlantic Oscillation (NAO) have a marked signature on the ozone layer. The recent realisation that the NAO is part of a more global pattern, termed the Arctic Oscillation (AO), which extends from the surface upwards into the stratosphere, highlighted the coupling of the NAO with the stratosphere and the ozone layer. We examine nearly 20 years of global TOMS observations, and diagnose the signatures of the leading patterns of climatic variability upon total ozone. Our main emphasis is on the E uropean and Atlantic sector. These signatures are twofold. We seek for influences on both the seasonal-mean (quasi-stationary) ozone, and else on the fast transient (eddy) ozone variability linked to passing weather systems. We hence systematically examine how leading climate patterns influence seasonal-mean ozone in winter and spring, through a statistical analysis using empirical orthogonal functions. In addition, we carried out an analysis of ozone synoptic variability. Satellite column ozone observations indicate a strong signature of storm tracks in ozone, with marked asymm etries between the Pacific and Atlantic storm tracks. Of particular interest are the large amplitude ozone "mini-hole" events that frequently develop over the Atlantic in winter. We examine the relationship between the occurrences of such ozone minihole events and the NAO or other climate patterns.