Ozonesonde ozone vertical profiles as well as SAGEII ozone profiles are used to detect anomalous large ozone concentrations of ozone in the lower stratosphere. These secondary ozone maxima are found to be the result of differential advection of ozone-poor and ozone-rich air associated with Rossby wave breaking events. The frequency and intensity of secondary ozone maxima and their geographical distribution is presented. The occurence of ozone secondary maxima can be used as a measure of the influence of atmospheric circulation on the ozone distribution at mid-latitudes.