Dynamical control of NH and SH winter/spring total ozone from GOME observations in 1995-2002

Abstract

The abnormal high wave activity in austral spring 2002 led to the first observation of a major stratospheric warming in the southern hemisphere resulting in a net winter increase of mid- to high latitude total ozone until September 2002. In previous years chemical ozone depletion inside the Antarctic vortex was sufficiently high to reduce mean total ozone south of 50° in September to values slightly below that of March (fall) as observed by GOME during the period 1995-2001. This unusual event permits us to examine the interannual variability in total ozone and OCIO (the latter being an indicator of the level of chlorine activation inside the polar vortex) as measured by GOME combining data from the southern and northern hemisphere. It is shown that the absolute winter eddy heat flux between 43° and 70° latitudes at 100 hPa correlates extremely well (r = 0.97) with spring-to-fall ratio of total ozone polewards of 50° and anti-correlates with the winter integrated maximum OCIO column amounts (r = -0.94) using this combined data set. The unusual ozone ratio for austral winter/spring 2002 lies almost midway between typical values for Antarctica and those for recent cold Arctic winter/spring seasons.