Study of Aerosol Radiative Properties During Long-range Transport of Biomass Burning from Canada to Central Europe in July 2013

In July 2013, the massive forest fires in eastern Canada emitted into the atmosphere the products of biomass burning, i.e. absorbing aerosols. Recent studies show that absorbing aerosols have significant impact on climate system, which leads to positive top of the atmosphere radiative forcing, but biomass burning aerosols are rather neutral on the global radiation budget. The biomass burning aerosols from Canadian fires traveled across the Atlantic Ocean and reached Central Europe between July 6 and 16, 2013, with the highest intensity through July 8 to 10. Our presentation will be an analysis of the seasonal variability of those smoke events over Central Europe and it will present a complex study of the event from July 2013, measured and simulated with the application of various techniques, from numerical modeling through local remote sensing to satellite sensors. The modeling was created with HYSPLIT (back trajectories), MACC transport model for the purpose of assessing the long-range transport over the Atlantic Ocean and spatial distribution of the biomass burning over Central Europe . Local remote sensing measurements incorporate data from AERONET (Cimel sun-photometers) and Poland-AOD networks. Multi-wavelength lidar profiles were collected in three sites with the scope of over 10 km above ground level for the transported aerosols. The lidar data allowed the retrieval of backscatter and extinction coefficient profiles as well as micro-physical properties (effective radius, refractive index). Additional properties were collected with Microtops hand-held sun photometers and Multi-Filter Rotating Shadowband Radiometers. On the satellite level, the analysis was based on the data from three sensors. MODIS and SEVIRI delivered the area information on AOD and seasonal data on fires, and CALIOP profiles of particle depolarization ratio. The analysis of seasonal variability of smoke occurrence over Central Europe is presented as a background for the event described in details. Records of satellite data and reanalysis of models (MACC, NAAPS) simulations indicate that April-May and August-September are the months with the greatest soot optical depth over Central Europe, which corresponds with the peaks of fires detected by MODIS sensor.