Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 2 2005 10.5194/acpd-5-1241-2005 http://www.atmos-chem-phys-discuss.net/5/1241/2005/ http://www.atmos-chem-phys-discuss.net/5/1241/2005/acpd-5-1241-2005.html http://www.atmos-chem-phys-discuss.net/5/1241/2005/acpd-5-1241-2005.pdf 1241 1253 2005-03-09 Evidence for long-lived polar vortex air in the mid-latitude summer stratosphere from in situ laser diode CH<sub>4</sub> and H<sub>2</sub>O measurements G. Durry A. Hauchecorne IPSL, Service d’A&eacute;ronomie, UMR 7620, BP 3, 91371 Verri&egrave;res-le-Buisson C&eacute;dex, France GSMA, UMR 6089, Universit&eacute; de Reims, BP 1039, 51687 Reims, C&eacute;dex 2, France A balloon borne diode laser spectrometer was launched in southern France in June 2000 to yield in situ stratospheric CH<sub>4</sub> and H<sub>2</sub>O measurements. In the altitude region ranging from 20 km to 25 km, striking large spatial structures were observed in the vertical concentration profiles of both species. We suggest these patterns are due to the presence of long-lived remnants of the wintertime polar vortex in the mid-latitude summer stratosphere. To support this interpretation, a high resolution advection model for potential vorticity is used to investigate the evolution of the Arctic vortex after its breakdown phase in spring 2000.