1Institute of Environmental Physics (IUP), University of Bremen, Bremen, Germany
2University of Saskatchewan, Saskatoon, Canada
3Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA
4Department of Meteorology, Pennsylvania State University, Pennsylvania, USA
Abstract. Vertical profiles of the rate of linear change (trend) in the altitude range 15–50 km are determined from decadal O3 time series obtained from SCIAMACHY/ENVISAT measurements in limb viewing geometry. The trends are calculated by using a multivariate linear regression in the zonal bands 5° S–5° N (tropics), 50–60° N, and 50–60° S (mid- to high latitudes). Seasonal terms, the quasi-biennial oscillation, and solar cycle variations are accounted for in the regression. In the tropics, positive trends between 15 and 30 km and negative trends between 30 and 35 km are identified. Moderately positive O3 trends are found in the upper stratosphere of the tropics and midlatitudes. The explanation favoured for the observed positive and negative trends in the tropical lower and middle stratosphere is NOx chemistry. Comparisons between SCIAMACHY and EOS MLS in the tropics and at midlatitudes show good agreement. In the tropics, measurements from OSIRIS/Odin and SHADOZ are analysed resulting in very similar vertical profiles of the rate of linear change of O3. Observed trends in the stratospheric column derived from integrated SCIAMACHY limb O3 profiles and nadir total columns are found to be consistent.