Fourteen-year series of vertical ozone distribution over Arosa,Switzerland, from Umkehr measurements

Summary Observations of the vertical ozone distribution over Arosa, Switzerland, have been carried out routinely since 1956 (with one two-year gap). Long-term trends of ozone concentration at different levels indicated by this series are discussed in the light of the results obtained from five years of parallel measurements with two Dobson spectrophotometers. Further substantiation of the suggested correlation between ozone concentration in the upper stratosphere and solar activity (with a two- to three-year lag of ozone against sun-spot numbers) is needed because no full agreement was obtained from the two instruments with respect to the secular variation at those top levels.