Mt. Brocken, a site for cloud chemistry measurement programme in central Europe

The author present results from the Brocken Cloud Chemistry Measurement Project (BROCCMON) which started in 1992. Since 1992 the full programme has been running, based on continuous measurements (e.g. trace gases, meteorology, liquid water content), cloud water sampling and analysis and intensive measurement campaigns. The observed high variability of cloud water composition is explained with cloud dynamic and microphysical behaviour of clouds and differences in the air mass characteristics. During the measurement period 1992-1994 an increase in cloud water acidity (by a factor of 3) was observed and photochemical conditions were found typically for summersmog situations. Preliminary data also show that an understanding of tropospheric ozone balance would be incomplete without consideration of chemical processes within clouds. A long-term goal of the programme is to establish a cloud chemistry climatology which is representative for the region. 12 refs., 2 figs., 1 tab