Collaborative Proposal: Aerosol Concentrations, Sources and Transport Pathways within the Arctic Polar Dome during Recent Millennia

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.

气溶胶在气候强迫中的作用举足轻重，但尚未得到充分认知。本项目的核心研究目标有二：（1）针对北极极地穹顶内的两处冰芯观测站点，构建独具特色的高时间分辨率、千年尺度气溶胶记录序列，涵盖生物质燃烧气溶胶、沙尘气溶胶、火山气溶胶、工业污染气溶胶及海盐气溶胶；（2）借助新开发及整合复用的通用环流模式（General Circulation Models, GCM）与其他模拟工具，解读本项目冰芯记录及极地穹顶外的同类冰芯记录，以明晰气溶胶向北极不同区域传输的源区与路径，及其对气候与环境的影响。

研究团队将对北极两侧两处低海拔站点的存档冰芯开展分析，以高深度分辨率（年采样量超50次）测定其中气溶胶的35余种元素与化学成分：其一为格陵兰极东北部弗拉德冰盖（Flade Isblink）的430米冰芯，由哥本哈根大学于2006年采集；其二为俄罗斯北极地区科学院冰盖（Akademii Nauk）的724米冰芯，由阿尔弗雷德·魏格纳研究所（Alfred Wegener Institute, AWI）于1999至2001年采集。

本项研究基于近年已发表的浅冰芯同类分析成果开展。弗拉德冰盖将提供北冰洋北大西洋扇区低层对流层气溶胶的逾3500年记录——该区域对北极海冰变化尤为敏感；而科学院冰盖则将提供欧亚大陆北部过往气溶胶的逾3000年记录，以及来自东亚的沙尘与污染物记录。

通过将仪器观测记录延伸至近数百年乃至数千年尺度，本批新一代冰芯记录结合模型模拟结果，将革新学界对半球尺度大气环流、跨极锋气溶胶传输，以及气候与气溶胶间反馈机制的全新世晚期与近代变化的认知。