Linear changes/trends in stratospheric O3 and BrO as seen by SCIAMACHY limb measurements during the decade 2002-2012

Abstract

This thesis contributes to the understanding of the temporal evolution of stratospheric ozone as well as bromine monoxide, which is an ozone-depleting substance, during the decade 2002-2012. It is based on data from the satellite instrument SCIAMACHY on board of the European research satellite ENVISAT (2002-2012). Vertically resolved time series of ozone and bromine monoxide are investigated. A comprehensive trend analysis is performed using the concept of linear changes/trends. Long-term changes exhibited by the time series are identified and quantified. They are confirmed by instrument comparisons between SCIAMACHY and other measurements. Consistent with a decline of the stratospheric halogen load, decreases of BrO were found throughout the lower stratosphere. Increases of ozone in the upper stratosphere support the onset of an ozone recovery. In addition, an increase in the lower stratosphere as well as a pronounced decrease in the middle stratosphere were detected in tropical ozone. This co-occurrence of positive and negative changes was, until recently, a rather unexpected phenomenon.