Optical characteristics of biomass burning aerosols over Southeastern Europe determined from UV-Raman lidar measurements V. Amiridis1, D. S. Balis2, E. Giannakaki2, A. Stohl3, S. Kazadzis2,4, M. E. Koukouli2, and P. Zanis5 1Institute for Space Applications and Remote Sensing, National Observatory of Athens, Athens, 15236, Greece 2Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece 3Norwegian Institute for Air Research, Kjeller, Norway 4Research and Development, Finnish Meteorological Institute, Helsinki, Finland 5Dept. of Meteorology and Climatology, Aristotle University of Thessaloniki, Thessaloniki, Greece
Abstract. The influence of smoke on the aerosol loading in the free troposphere over
Thessaloniki, Greece is examined in this paper. Ten cases during 2001–2005
were identified when very high aerosol optical depth values in the free
troposphere were observed with a UV-Raman lidar. Particle dispersion
modeling (FLEXPART) and satellite hot spot fire detection (ATSR) showed that
these high free tropospheric aerosol optical depths are mainly attributed to
the advection of smoke plumes from biomass burning regions over
Thessaloniki. The biomass burning regions were found to extend across Russia
in the latitudinal belt between 45° N–55° N, as well as in
Eastern Europe (Baltic countries, Western Russia, Belarus, and the Ukraine).
The highest frequency of agricultural fires occurred during the summer
season (mainly in August). The data collected allowed the optical
characterization of the smoke aerosols that arrived over Greece, where
limited information has so far been available. Two-wavelength backscatter
lidar measurements showed that the backscatter-related Ångström
exponent ranged between 0.5 and 2.4 indicating a variety of particle sizes.
UV-Raman lidar measurements showed that for smoke particles the extinction
to backscatter ratios (so-called lidar ratios) varied between 40 sr for
small particles to 100 sr for large particles. Dispersion model estimations
of the carbon monoxide tracer concentration profiles for smoke particles
indicate that the variability of the optical parameters is a function of the
age of the smoke plumes. This information could be useful on the lidar
community for reducing uncertainty in the aerosol backscatter coefficient
determination due to the lidar ratio assumption, starting from a simply
elastic backscatter lidar as the first satellite-borne lidar CALIPSO.
Citation: Amiridis, V., Balis, D. S., Giannakaki, E., Stohl, A., Kazadzis, S., Koukouli, M. E., and Zanis, P.: Optical characteristics of biomass burning aerosols over Southeastern Europe determined from UV-Raman lidar measurements, Atmos. Chem. Phys., 9, 2431-2440, doi:10.5194/acp-9-2431-2009, 2009.