Regensburg 1998 – wissenschaftliches Programm

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SYA: Symposium Physik für die Umwelt

SYA 2: Sondersymposium “Physik für die Umwelt” – Wissenschaftliche Poster

SYA 2.64: Poster

Dienstag, 24. März 1998, 16:45–19:00, C

Match: Measurements of Arctic Stratospheric Ozone Depletion Rates — •M. Rex and P. von der Gathen — Alfred Wegener Institute, PO Box 600149, D-14401 Potsdam

A Lagrangian approach has been developed to perform in-situ observations of chemically induced ozone loss in the Arctic lower stratosphere. The technique is based on the statistical analysis of a large number of so called ’matches’. A match is defined as a pair of ozonesonde measurements where sondes are launched from different stations and at different times but probe the same air parcel as it passes by. Chemical ozone destruction rates were achieved in temporal and vertical resolution in four recent winters. In each of the covered winters ozone loss with rates up to 1.5 to 2 % per day was found. Fast ozone loss was always preceded by periods with temperatures cold enough for PSCs to form in the respective altitude level. Ozone loss occurred exclusively during sunlit periods along the trajectories. These observations confirm our current understanding of heterogenous activation of chlorine reservoirs on PSC surfaces followed by photochemical ozone destruction by chlorine radicals. In a limited altitude region, where temperatures had been extremely low during winter 95/96, ozone loss persisted unusually long after the springtime warming. This is the first observation of typical Antarctic conditions in the Arctic, demonstrating how sensible the Arctic ozone loss reacts on small temperature differences. Larger Arctic ozone losses can be expected in future if the apparent cooling trend in the Arctic stratosphere is real.