Tropospheric ozone interannual variability at Mt. Cimone WMO/GAW global station (2165 m a.s.l., Italy)

We analysed 21 years of surface O3 data at the Mt. Cimone station (2165 m, Italy). High O3 values were observed during summer in the Mediterranean region. O3 increased over 1991-2011, no trends were detected for the 1996-2011. Negative trend (-0.13 nmol/mol/year) for the period 1996 - 2013 . Summer O3 growth-rates showed a slowing-down in recent years. O3 minima appeared to be related with high contributions of Southerly air-masses at CMN