ON A PERIOD WITH VERY-LOW OZONE CONCENTRATIONS WITHIN THE LOWER STRATOSPHERE

The Hohenpeissenberg ozone data reveals a conspicuous ozone decrease d uring the winter of 1991/92. Compared with the long-term mean, a decre ase of about 10% could be observed in total ozone. A decrease of about 25% in the lower stratosphere was also seen. The possible causes for this ozone reduction were examined. At first die existing ozone trend which is considered to be caused by CFCs was eliminated. Because of co ntemporary, frequent high-pressure situations over Europe, this dynami c influence was also estimated and eliminated. There still remains an ozone deficit, showing that there must be additional reasons. Here the aerosols from Pinatubo should be considered.