Left column: Ozone time series of the daily amplitude. Right column: Box-whisker plots of the statistical distribution of the summer amplitude data for every year that had at least 80% of data available for a given year. Linear regression fits trough the 5^th, 50^th and 95^th percentile of the data for each year show the trend behaviour. Regression analysis slope results (in ppbv yr^–1) are given in the legends. DOI: https://doi.org/10.1525/elementa.300.f8