Equivalent Black Carbon in the Arctic

S. Sharma, J. A. Ogren, A. Jefferson, K. Eleftheriadis, E. Chan, P. K. Quinn and J. F. Burkhart Environment Canada, Atmospheric Science and Technology Directorate, 4905 Dufferin Street, Toronto, Ontario Canada NOAA Earth System Research Laboratory, 325 Broadway, Boulder, CO 80305-3337 Institute of Nuclear and Radiological Science & Technology, Energy & Safety N.C.S.R. "Demokritos" 15310 Ag. Paraskevi, Attiki, Greece NOAA Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA, 98115 University of Oslo, Department of Geosciences, PO Box 1047 Blindern, N-0316 Oslo Highlights Equivalent Black Carbon (EBC) has declined by as much as 55% over the 23 year record at two high Arctic surface locations. This decline has been related to changes in BC emissions in the early 1990s in the mid-latitude source regions especially in the Former Soviet Union. Increases in BC emissions in the 2000s in East Asia have had no observed effect on the surface concentrations at three measurement locations. Averaged EBC concentrations in 2012 at all three locations are similar to the averaged EBC concentrations over the last decade. A comparison of anomalies in EBC concentration at the three Arctic locations indicates that each site is unique in terms of transport pathways of pollution from the mid-latitude BC source regions to the site and depositional loss of BC en route to or at the site.