Biomass Burning, Dust, Sea Salt, Volcanic & Pollution Aerosols in the Arctic during the Last 2 Millennia: High Resolution Aerosol Records from NEEM & an Aray of Archived Ic

该奖项将支持开发和解释新一代的短寿命气溶胶记录，这些记录是在过去2000年和过去13万年的特定时间段内，由北极的生物质燃烧、灰尘、海洋喷雾、火山活动和工业污染产生的。这些目标将使用一个独特的、由美国国家科学基金会资助的分析系统来完成，该系统是专门为在冰芯中进行这种测量而开发的，最近扩展到包括黑碳（BC；烟灰）和一系列新的气溶胶源示踪剂的详细测量。对过去2000年气溶胶的拟议测量——建立在最近发表的一系列对较浅冰芯的类似测量结果的基础上——将对丹麦合作者于2008年和2009年在格陵兰北部的NorthEem （NEEM）钻探点收集的400米浅冰芯样本进行测量。为了将NEEM测量结果置于更大的北极和全球视角，还将分析来自约1000年存档的北极冰芯的广泛样本，并将北极测量结果与已经在南极冰芯中进行的类似世纪至千年尺度的气溶胶测量结果进行比较。知识价值：地球气候的自然变化在古气候记录中得到了很好的记录，但是由深冰芯提供的气候历史需要更好地理解最近的气候变化是如何影响不同地区的，以及高、中、低纬度过程之间的关系。短寿命气溶胶——包括由野火产生的气溶胶——是重要的环境和全球气候强迫因子，由于雪反照率反馈，当沉积在冰雪中时，对北极强迫尤为重要。它们的来源主要在低纬度和中纬度地区，但它们对极地地区的影响是深远的——由于缺乏可靠的长期测量而难以量化。从NEEM和存档的冰芯中得到的丰富的冰川化学记录，特别是与类似的南极冰芯气溶胶记录和通过协作模拟研究合成的结果相比较，将改变全球对短寿命BC、灰尘、火山、海盐和污染气溶胶的来源和历史及其对气候强迫、生态系统和人类健康的影响的认识。此外，由于野火排放是直接调节温室气体浓度的一个因素，本研究和相关南极研究提供的独立的野火排放历史将有助于定量解释NEEM和WAIS分水岭深层冰芯中测量到的温室气体浓度变化。更广泛的影响：政策决策以全球气候模式（GCM）对不同社会行为情景下的气候预测为指导；气候预测在很大程度上依赖于调整良好、经过验证的模型。尽管IPCC确定的气溶胶强迫存在很大的不确定性，但由于过去冰芯气溶胶测量的范围和可靠性有限，因此很少将冰芯气溶胶记录用于GCM校准、参数化或调优。该冰芯分析系统的新一代气溶胶测量是合适的，并使最近与GCM社区的合作成为可能。为了确保拟议的研究在气候变化和政策领域产生最广泛的影响（例如，最近在美国国会关于短期污染物和北极气候变化的证词），将扩大与NCAR、NOAA/GFDL和NASA/GISS建模师的合作，将拟议的冰芯测量纳入GCM研究。该提案还直接解决了美国国家科学基金会（nsf）赞助的国际冰芯科学伙伴关系（IPICS）倡议的要点——开发一系列详细的冰芯记录，跨越过去2000年，旨在更好地理解长期气候记录，彻底改进，定量调查最近的气候变化和人类活动在气候强迫和环境中的作用。NEEM项目提供了许多国内和国际的教育和推广机会。提议的努力将充分利用这些机会，并继续长期记录高中生、本科生和研究生以及博士后在实验室的参与；K-12教育工作；通过高知名度的出版物以及与公众、大众媒体和决策者的接触来传播结果。

This award will support the development and interpretation of a new generation of records of short-lived aerosols from biomass burning, dust, sea spray, volcanism, and industrial pollution in the Arctic during the past 2000 years and for selected time periods during the past 130,000 years. These objectives will be accomplished using a unique, NSF-funded analytical system developed specifically for such measurements in ice cores and recently expanded to include detailed measurements of black carbon (BC; soot) and a range of new aerosol source tracers. Proposed measurements of aerosols during the past 2000 years - building on a series of recently published findings from similar measurements in shallower ice cores - will be made on samples from a 400 m shallow core collected by Danish collaborators in 2008 and 2009 at the NorthEem (NEEM) drilling site in northern Greenland. To place the NEEM measurements in larger Arctic and global perspective, samples from a broad array of ~1000 year archived Arctic ice cores also will be analyzed and results from the Arctic measurements compared with similar century to millennial scale aerosol measurements already underway in Antarctic ice cores.Intellectual Merit: Natural changes in the Earth's climate are well documented in paleoclimate records, but the climate history provided by deep ice cores needs to be complemented by better understanding of how recent climate changes have affected different regions and relationships among high-, mid-, and lowlatitude processes. Short-lived aerosols - including those generated by wildfires - are important environmental and global climate forcing agents and, because of the snow-albedo feedback, particularly important to Arctic forcing when deposited in snow and ice. Their sources are primarily in the low- and mid-latitudes, but their impacts on the Polar Regions - poorly quantified because of the paucity of reliable, long-term measurements - are profound. The rich glaciochemical records developed from the NEEM and archived ice cores, especially when compared to similar Antarctic ice core aerosol records and the results synthesized through collaborative modeling studies, will transform global understanding of the sources and histories of short-lived BC, dust, volcanic, sea salt, and pollution aerosols and their impacts on climate forcing, ecosystems, and human health. Moreover, because wildfire emissions are one factor directly modulating GHG concentrations, the independent history of fire emissions provided by this and related Antarctic research will contribute to a quantitative interpretation of changing GHG concentrations measured in the deep NEEM and WAIS Divide ice cores.Broader Impacts: Policy decisions are guided by global climate model (GCM) predictions of climate under different scenarios of societal behavior; climate predictions are critically dependent on well-tuned, validated models. Despite large uncertainties in aerosol forcing identified by the IPCC, ice core aerosol records seldom are used in GCM calibration, parameterization, or tuning because of the limited scope and reliability of past ice core aerosol measurements. New generation aerosol measurements from this ice core analytical system are suitable and have enabled recent collaborations with the GCM community. To ensure the broadest impact of the proposed research in climate change and policy arenas (e.g., recent testimony before the U.S. Congress on short-lived pollutants and Arctic climate change), ongoing collaborations with modelers at NCAR, NOAA/GFDL and NASA/GISS will be expanded to incorporate the proposed ice core measurements into GCM studies. This proposal also directly addresses a thrust of the NSF-sponsored International Partnerships in Ice Core Sciences (IPICS) initiative - development of an array of detailed ice core records spanning the last 2000 years aimed at better understanding long-term climate records thorough improved, quantitative investigation of recent climate change and the role of human activities in climate forcing and on the environment. The NEEM project provides many national and international opportunities for education and outreach. The proposed effort will leverage these opportunities to the fullest extent and continue the long-term record of high school, undergraduate and graduate student, and post-doctoral fellow involvement in the laboratory; K-12 educational efforts; and dissemination of results through high visibility publications and outreach to the public, popular media, and policy makers.