BIOMASS BURNING IMPACT ON BLACK CARBON AEROSOL MASS CONCENTRATION AT A COASTAL SITE: CASE STUDIES

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 degrees 55' N, 21 degrees 00' E, 5 m a.s.l., Lithuania). The surface measurements and calculation of Angstrom exponent of the absorption coefficient alpha carried out separately for shorter and longer wavelengths (i.e., lambda = 370-520 nm and lambda = 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 oft-hour average reached 13000 ng m(-3), while normally annual mean concentration values are about 750 ng m(-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 Angstrom exponent of the absorption coefficient alpha(370-520) and alpha(590-950) were observed (2.0 +/- 0.4 and 1.6 +/- 0.3, respectively). The mean values of Angstrom 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.