Interpretation of the High Resolution, Multivariate Mt. Logan (Yukon Territory) Ice Core - A Record of North Pacific Climate and Atmospheric Chemistry

最近建立的洛根山冰芯冰川化学数据集为了解全新世气候变化以及北太平洋大气中自然和人为化学物质的来源和通量提供了前所未有的机会。利用改进的连续冰芯熔化系统，对185米长的冰芯进行了高分辨率采样，并分析了40多种化学物质，包括主要离子、微量元素、稀土元素和稳定同位素。跨越前500年~500年的亚季节样本允许进行年度层计数，然后对跨越全新世和部分晚冰期的剩余时间尺度进行冰流模拟。它的连续和高分辨率的样本，共同登记的化学测量的广度，北太平洋自由对流层的时间跨度和位置，使洛根山冰川化学数据集成为冰芯分析的新基准，具有理解古气候变率和大气化学的潜力，远远超出了即将完成的初始项目的界限。对罗根山新记录的解释表明，来自亚洲的人为污染物。自20世纪70年代初以来污染了北太平洋自由对流层。洛根山沙尘和海盐浓度分别与亚洲沙漠和太平洋源区的大气压力中心具有统计上显著的相关性。研究生和随后的博士后研究员需要资金，继续解释这一独特的记录，并从现有的样品和存档的岩芯中产生额外的化学时间序列。该研究生负责扩展缅因大学的连续融冰系统能力，制作洛根山冰川化学记录，并解释数据集，因此对数据集和研究区域具有预先存在的广泛知识。拟议活动的学术价值：这项研究将建立在先前对洛根山记录的解释基础上，同时增加特定的新时间序列，以澄清亚洲人为金属和自然粉尘的来源。它将直接有助于理解：1)人为和自然气溶胶排放及其来源，特别是来自亚洲；2)千年尺度北半球全新世气候变率和强迫机制；3)年至年代际尺度北太平洋全新世气候变率和强迫机制；4)北太平洋最近的气候变化在气候上与地球有关，到目前为止，对温室气体变暖反应最大的地区，北极。利用多元统计和时间序列分析，将洛根山峰顶记录与低海拔冰芯、树木年轮、湖泊和海洋沉积物岩芯、冰川和现有气候强迫记录的区域代用记录进行比较，研究北太平洋年-千年气候波动的时间、强度和强迫机制。将通过比较洛根山记录与全球分布地点的冰芯和古气候代理记录，研究北半球和热带气候模式之间的联系以及全球全新世气候变化的性质。更广泛的影响：对该记录的解释将有助于了解北美、太平洋和亚洲未来气候变化的可能性，以及亚洲国家土地利用变化和工业化对北美大气的影响。本项目所产生的所有数据将提供给WDC- a的冰川学和WDC的古气候学。

ABSTRACTMayewskiOPP-0612400The recently developed Mt. Logan ice core glaciochemical dataset provides an unprecedented opportunity to understand Holocene climate change and the sources and fluxes of natural and anthropogenic chemicals in the North Pacific atmosphere. The 185 m-long ice core has been sampled at very high resolution using a refined and updated continuous ice core melter system, and analyzed for over 40 chemical species, including major ions, trace elements, rare earth elements, and stable isotopes. Subseasonal samples spanning the top ~500 years allow for annual layer counting, followed by ice flow modeling for the remainder of the timescale spanning the Holocene and portions of the late glacial period. Its continuous and high-resolution samples, breadth of co-registered chemical measurements, time span and location in the North Pacific free troposphere make the Mt. Logan glaciochemical dataset a new benchmark in ice core analyses with the potential for understanding paleoclimate variability and atmospheric chemistry far beyond the boundaries of the soon to be completed initial project. Interpretation of the new Mt. Logan record suggests that anthropogenic pollutants from Asia.have contaminated the North Pacific free troposphere since the early 1970s. Mt. Logan dust and sea-salt concentrations show statistically significant correlations to atmospheric pressure centers over their Asian desert and Pacific Ocean source regions, respectively. Funds are requested for a graduate student, and subsequent post-doctoral researcher, to continue interpretation of this unique record, and produce additional chemical time series from existing samples and archived core. This graduate student was responsible for expanding the University of Maine capabilities continuous ice melter system, producing the Mt. Logan glaciochemical record, and interpreting the dataset, and consequently has pre-existing, extensive knowledge of the dataset and the study area.Intellectual Merit of the Proposed Activity: This research will build upon previousinterpretations of the Mt. Logan record, while adding specific new time series to clarify the sources of Asian anthropogenic metals and natural dust. It will directly contribute to the understanding of:1) Anthropogenic and natural aerosol emissions and their sources, particularly from Asia,2) Millennial scale Northern Hemisphere Holocene climate variability and forcing mechanisms,3) Annual to decadal scale North Pacific Holocene climate variability and forcing mechanisms,4) Recent climate change in the North Pacific that is climatologically linked to Earth's, thus far, region of greatest response to greenhouse gas warming, the Arctic.Using multivariate statistics and time series analyses, the timing, intensity and forcing mechanisms of North Pacific annual to millennial climate fluctuations will be investigated by comparing the Mt. Logan summit record to regional proxy records from ice cores at lower elevations, tree rings, lake and marine sediment cores, glaciers, and existing climate forcing records. Links between northern hemisphere and tropical climate patterns and the nature of global Holocene climate shifts will be investigated by comparing the Mt. Logan record to ice core and paleoclimate proxy records from globally distributed locations.Broader Impacts: Interpretations from this record will contribute to understand the potential for future climate changes over North America, the Pacific and Asia, and the impact of land-use changes and industrialization by Asian countries on the North American atmosphere. All data produced by this project will be provided to WDC-A for Glaciology and WDC for paleoclimatology.