| Abstract: | GOAL, SCOPE AND BACKGROUND: Great interest in the unprecedented events of the major, sudden stratospheric warming and the ozone hole split over Antarctica in September 25, 2002 motivates a necessity to analyze the current understanding on the dynamics, chemistry and climate impacts that are associated with both events. METHODS: Significant progress in the analysis of the observational data obtained, as well as successful development and application of dynamical modeling, which have been achieved very recently, create a basis for the first survey on the role of the major, sudden stratospheric warming observed in the southern hemisphere and its relationship to the diminutive Antarctic ozone hole and its break up into two parts. RESULTS AND DISCUSSION: Special attention has been paid to assessments of the causes of the major warming event and the future expectations concerning the stratospheric ozone depletion effect. Among the principal results is the fact that, as the polar vortex elongated, it became hydrodynamically unstable, and this insta-, bility affected the upper troposphere and stratosphere. During the major, sudden stratospheric warming, the middle stratospheric vortex split into two pieces; one piece rapidly mixed with extra vortex air, while the other returned to the pole as a much weaker and smaller vortex. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters, resulting from a series of wave events (propagated from the troposphere) that took place over the course of the winter. Finally, the relative ozone decrease (increase) in the eastern Antarctic is tightly associated with westerly (easterly) zonal wind anomalies near the southern tip of South America, and the unusual behavior of the ozone hole in 2002 therefore appears to be caused by great easterlies in this region. CONCLUSIONS: The main conclusion is that the southern polar vortex and the diminutive ozone hole split into two parts in September 2002, due to the prevalence of very strong planetary waves, led to the appearance of a major, sudden stratospheric warming. Although there is evidence that sea surface temperature anomalies contributed to the excitation of the quite strong planetary waves over Antarctica in 2002, there is not yet a widely approved mechanism supporting that. RECOMMENDATIONS AND OUTLOOK:The appearance of the near-record size of the 2003 ozone hole confirmed that the 'no-ozone-hole' episode observed in the year 2002 does not denote a recovery of the ozone layer. Despite the current successful attempts to get a sufficient understanding for the genesis of both extraordinary events, more observations and further modeling efforts are necessary to more reliably assess the contribution of various dynamic mechanisms to the recently observed tropo-stratospheric surprises. |
