| Summary: | The role of aerosols in climate forcing is significant but poorly understood. The primary goals of this project are to (1) develop unique high-time-resolution, millennial-scale records of biomass burning, dust, volcanic, industrial pollution, and sea salt aerosols for two ice core sites inside the Arctic polar dome and (2) use new and leveraged general circulation models (GCM) and other modeling to interpret these and similar ice core records from outside the polar dome to better understand source regions and transport pathways of aerosols to different regions of the Arctic and their climatic and environmental impacts. Measurements of >35 elemental and chemical components of these aerosols will be made at high depth resolution (>50 measurements per year) in archived ice cores from two lower elevation sites on opposite sides of the Arctic: a 430 m core collected by the University of Copenhagen in 2006 from Flade Isblink ice cap in far northeastern Greenland and a 724 m core collected by the Alfred Wegener Institute (AWI) in 1999 to 2001 from Akademii Nauk ice cap in the Russian Arctic. The measurements build on recently published findings from similar analyses in shallower ice cores. Flade Isblink will provide a >3500 year record of aerosols in the lower troposphere in the North Atlantic sector of the Arctic Ocean ? a region particularly sensitive to changes in Arctic sea ice ? while Akademii Nauk will provide a > 3000 year record of past aerosols in northern Eurasia, as well as dust and pollutants from eastern Asia. By extending instrumental records to recent centuries and millennia, this new generation of ice core records, coupled with model simulations, will transform understanding of recent and late Holocene changes in hemispheric atmospheric circulation, aerosol transport across the polar front, and feedbacks between climate and aerosols.
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