Calibration and Reconstruction of Temperature and Precipitation Change in Arctic Lakes

主要研究人员将根据北极湖泊的有机生物标志物校准新的温度和降水代理。他们将在巴芬岛地区表层湖泊样本的密集空间网络中测量一种新型四醚生物标志物的独立温度和陆地径流指数。他们将根据巴芬岛的陡峭温度和降水梯度校准这些生物标志物指数，并将其延伸到冰岛、拉布拉多、南格陵兰岛以及加拿大北部群岛。这个地表沉积物网络将使他们能够开发出低温的湖泊温度代理，并为降水数据提供径流指数的首次校准。来自冰岛和巴芬岛的长沉积物岩心将成为整个全新世及以后的高分辨率古气候记录的目标，以量化末次消冰期和全新世热最大值期间的变暖程度。他们还将量化末次间冰期的温度变化。这些时间间隔代表了更温暖的时间段，这些时间段在定量温度方面受到的约束很差，但对于估计未来变暖对北极环境的影响至关重要。准确记录北极气候变化的模式和时间对于理解全球气候系统的运作方式非常重要。就气候而言，北极是一个具有全球意义的地区，全球气候变化的影响可能在其他地方发现之前就在北极被识别出来，正如近年来整个北极环境记录的大规模和快速变化所表明的那样。除了显示出对全球气候变化的敏感性外，北极还可能迫使广泛的气候变化，因此，北极气候变化的详细记录对于构建全球系统的综合图景至关重要。北极是区分气候自然强迫和人为强迫的重要区域，这与近几个世纪的快速变暖特别相关，因为古气候记录表明，人类对最近变暖的贡献超过了自然强迫机制的贡献。气候代用物的精确校准对于解决区域汇编之间的差异、得出当前变暖幅度的可靠估计以及量化北极过去可能无冰期间的变暖至关重要。更广泛的影响：本研究将为一名女性博士后学者和一名女性研究助理提供研究机会和培训。这些科学家将受益于学习尖端有机地球化学分析技术的直接经验，并将有机会旅行，与不同的研究小组互动，并在国际会议上展示他们的成果。主要研究人员积极与公众和决策者接触。具体的活动包括对科学记者和美国国会代表的讲座，以及对电视和国内外新闻机构的采访。本研究将探讨利用有机生物标志物重建北极湖相沉积物的湖泊温度和降水记录。他们将使用多种平行化合物和分析技术来最大限度地从沉积物中提取信息。在沉积物中使用有机生物标志物来研究古气候过程仍然是一个年轻的领域，他们预计，从提出的分析中产生的丰富数据将导致新的见解和新的基于生物标志物的环境代用物的发展。

ABSTRACT OPP-0520266HughenThe Principal Investigators will calibrate new proxies for temperature and precipitation basedon organic biomarkers in Arctic lakes. They will measure independent temperature and terrestrial runoff indices from a new class of tetraether biomarkers within a dense spatial network of surface lake samples from the Baffin Island region. They will calibrate these biomarker indices to steep temperature and precipitation gradients across Baffin Island and extending to Iceland, Labrador and S. Greenland as well as the northern Canadian Archipelago. This surface sediment network will allow them to develop a lake temperature proxy for low-temperatures, and provide the first calibration of a runoff index to precipitation data. Long sediment cores from Iceland and Baffin Island will be targeted for high-resolution paleoclimate records throughout the Holocene and beyond, to quantify the degree of warming during the last deglaciation and Holocene Thermal Maximum. They will also quantify temperature changes during the Last Interglaciation. These intervals represent time periods of greater warmth that are poorly constrained in quantitative temperature, but are critical for estimating the impacts of future warmth on Arctic environments.Intellectual MeritAccurate records of the pattern and timing of climate change in the Arctic are important tounderstanding how the global climate system functions. The Arctic is a globally significant region with respect to climate, and the effects of global climate change might be identifiable in the Arctic before they can be found elsewhere, as suggested by the large and rapid changes documented throughout the Arctic environment in recent years. In addition to showing sensitivity to global changes in climate, the Arctic may also be capable of forcing widespread climate shifts, and detailed records of Arctic climate change are thus critical to the construction of an integrated picture of the global system. The Arctic is an important region for discriminating between natural and anthropogenic forcing of climate, which is particularly relevant for the rapid warming during recent centuries when paleoclimate records have implicated an anthropogenic contribution to recent warming, above and beyond the contribution from natural forcing mechanisms. Accurate calibrations of climate proxies are crucial to resolving differences between regional compilations and deriving reliable estimates of the magnitude of current warming, as well as quantifying warming during past intervals when the Arctic may have been ice-free.Broader Impacts: This study will provide research opportunities and training for one female Postdoctoral Scholar and one female Research Associate. These scientists will benefit from direct experience learning cutting-edge organic geochemical analytical techniques, and will have opportunities to travel, interact with different research groups, and present their results at international meetings. The Principal Investigators are active in outreach to the public and policy-makers. Specific activities include lectures to science journalists and Representatives to the U.S. Congress, as well as interviews for TV and domestic and international news organizations. The study will investigate the use of organic biomarkers to reconstruct lake temperature and precipitation records from Arctic Lacustrine sediments. They will use multiple parallel compounds and analytical techniques to maximize the information extracted from the sediments. The use of organic biomarkers in sediments for the study of paleoclimate processes is still a young field, and they anticipate that the wealth of data arising from the proposed analyses will lead to new insights and the development of new biomarkerbased environmental proxies.