From 16-24 April 2010 multiwavelength EARLINET Raman lidar and AERONET Sun photometer measurements were performed at the Leibniz Institute for Tropospheric Research (IfT) in Leipzig (51.3° N, 12.5° E), Germany, to monitor the ash layers originating from the eruptions of the Eyjafjallajokull volcano in southern Iceland. We observed the first ash plumes on 16 April 2010. They showed strong depolarization which indicates non-spherical particles. Extinction coefficients were as high as 500 Mm-1. We estimate ash mass concentrations of the order of 1000 μg/m3 in the main plume. For an aged ash plume on 19 April 2010 we observed much lower extinction coefficients of around 50 Mm-1 which lead to estimated ash mass concentrations of the order of 100 μg/m3.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.