| << | Profiling of Aerosols | >> |
Abstract
From the end of May 2008 one of the strongest Saharan Dust outbreaks ever reached Central Europe. It significantly influenced the aerosol load over Southern Germany for as long as one week. The optical properties of the aerosol particles as a function of time and height were derived from data of the lidar systems POLIS and MULIS of the Meteorological Institute of the Ludwig-Maximilians-Universität at Munich (48.14°N, 11.57°E) and Maisach (48.20°N, 11.25°E), respectively. Measurements include extinction coefficient, the linear particle depolarization ratio and the extinction to backscatter ratio at 355 nm and 532 nm. The data sets were supplemented with spectral optical depths derived from CIMEL sunphotometer measurements at Munich. The dust plume reached the measurement sites on May 26th with a southerly flow, lasting until June 2nd, only interrupted on May 30th and 31st by a front passage. The dust layer was located above the boundary layer (0.5 – 1 km above ground level) with an extent up to 4 – 5 km height. Preliminary analyses result in linear particle depolarization ratios of about 25 – 30 % at 532 nm, which indicate dust. The extinction coefficient within this layer ranges from 0.05 km-1 to 0.2 km-1, with maximum values of about 0.3 km-1. This analysis agrees very well with observations of – for Munich – atypically high total aerosol optical depths of up to 1 derived from the sunphotometer. The Angström exponent during the episode mainly range from 0.1 – 0.5, demonstrating the dominating contribution of the dust particles.