European research in the stratosphere - EASOE and SESAME
The European Commission, DG XII, has published a review of European research in the stratosphere from 1989 to 1995, including that conducted under the EASOE and SESAME experiments. Research on stratospheric ozone depletion was a key objective of the STEP (Science and Technology for Environmental Protection) programme from 1989 to 1992, and the Environment programme of the Third RTD Framework Programme (1991-1995). These Community programmes, complemented by several national programmes, resulted in a balanced and coordinated research programme into ozone depletion, which culminated in two major experiments: EASOE (1991-1992) and SESAME (1994-1995). The European Arctic Stratospheric Ozone Experiment (EASOE) was organized in the winter of 1991-1992. Its main aim was to study the evolution of the Arctic stratosphere during winter conditions, in particular the concentration and behaviour of ozone and other chemicals. SESAME, the Second European Arctic and Mid-latitude Experiment, was conducted in 1994 and 1995. By taking measurements at different times of year, in both the Arctic region and mid-latitudes, this experiment aimed to compare the stratospheric process in the two regions and determine to what extent they are linked. The report outlines the background to the research and the methodology and tools used. It then outlines the main results obtained in the following areas: - Meteorology and atmospheric transport; - Particles in the stratosphere; - Stratospheric chemistry; - Ozone loss; - UV radiation at the earth's surface.