Biomass burning impact on black carbon aerosol mass concentration at a coastal site: Case studies

Abstract

During 25 March – 5 April 2010 intense wildfires in the Kaliningrad region (Russia) occurred. The resultant smoke plume blanketing the Lithuanian western part was seen in satellite images. Concurrently, an extremely high black carbon (BC) aerosol mass concentration was observed at the background Preila site (55°55' N, 21°00' E, 5 m a.s.l., Lithuania). The surface measurements and calculation of Ångström exponent of the absorption coefficient carried out separately for shorter and longer wavelengths (i. e., λ =370–520 nm and λ =590–950 nm) showed that high levels of BC aerosol were related to the transport of air masses rich in biomass burning products from the Kaliningrad region caused by active grass burning. During this event the BC aerosol mass concentration of 1-hour average reached 13000 ngm−3, while normally annual mean concentration values are about 750 ngm−3. The transport of the burning products from fire areas is associated with southeastern flow and strong advection of warm and dry air from South Europe in the lower troposphere. During the event the highest mean values of Ångström exponent of the absorption coefficient α370−520 and α590−950 were observed (2.0±0.4 and 1.6±0.3, respectively). The mean values of Ångström exponent of the absorption coefficient during the study period obviously indicate that a major part of carbon mass in aerosol particles transferred by the regional air masses comes from the wildfire location. : black carbon aerosol, aethalometer, biomass burning, Ångström exponent of the absorption coefficient