| Summary: | In spring 2010 the Icelandic volcano Eyjafjallajokull erupted high loads of pyroclastic material into the atmosphere. The eruption cloud reached heights between 4 and 7 km. The volcanic ash advisory centre London, the responsible institution for making forecasts of ash coming to Europe, decided the complete shut down of the air traffic over wide parts of Europe for a sequence of days. From April 13th to 20th there was a stable high pressure system over the Atlantic Ocean. Thus, a rather constant air flow from north-west to south-east prevailed over Europe in the upper and middle troposphere. Due to that the volcanic ash was transported from Iceland over the UK to Central Europe. Furthermore, the weather conditions were sunny, dry, and stable, preventing the ash from being mixed throughout the atmosphere or from being washed out by precipitation. These weather conditions led not only to long range ash transport but also to high PM10 concentrations in the boundary layer from other sources. Thus the question arises whether the volcanic ash contributed to the high PM10 levels near ground or if the reason for the high PM10 concentrations measured by the ground based stations has to be found elsewhere. The aim of this paper is to give a review of some of the findings of the ground based measurements, model calculations, and remote sensing in Central Europe during the volcanic event two years ago, with focus on Germany, France, and Great Britain. A large variety of modelling results on the dispersion of the Eyjafjallajokull plume over Europe can be found in the recent literature. They all showed that the ash plume reached the air space over Central Europe and these findings compare rather nicely to satellite pictures, Lidar measurements, and measurements from aircrafts. In the present paper as an example EURAD and Chimere model simulations will be presented. With regard to lidar and satellite measurements, we will concentrate on the findings by the German Weather Service, the Met Office and of the volcanic ash advisory ...
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