Dynamical evolution of the 2003 southern hemisphere stratospheric winter using Envisat trace‐gas observations

Data from the MIPAS instrument on Envisat, supplemented by meteorological analyses from ECMWF and the Met Office, are used to study the meteorological and trace‐gas evolution of the stratosphere in the southern hemisphere during winter and spring 2003. A pole‐centred approach is used to interpret the data in the physically meaningful context of the evolving stratospheric polar vortex. The following salient dynamical and transport features are documented and analysed: the merger of anticyclones in the stratosphere; the development of an intense, quasi‐stationary anticyclone in spring; the associated top‐down breakdown of the polar vortex; the systematic descent of air into the polar vortex; and the formation of a three‐dimensional structure of a tracer filament on a planetary scale. The paper confirms and extends existing paradigms of the southern hemisphere vortex evolution. The quality of the MIPAS observations is seen to be generally good, though the water vapour retrievals are unrealistic above 10 hPa in the high‐latitude winter. Copyright © 2006 Royal Meteorological Society