Reconstruction of climate at the Norse Settlements of Greenland over the last two millennia using organic biomarkers in lake sediments

格陵兰岛南部的气候是重建北大西洋涛动的关键区域，北大西洋涛动是北半球气候的主要模式，也与大西洋经向翻转环流变化有关，大西洋经向翻转环流是控制北大西洋气候的一个重要海洋过程，最近的研究表明，北大西洋气候在最近几十年比过去1000年的任何时候都要弱。15世纪早期，挪威人的定居点也被遗弃在这里；关于致病因素仍有许多疑问。虽然气候变化经常被引用为定居失败的原因，但这种解释建立在一个非常缺乏约束的科学基础上，其他解释也被提出。关于该地区气候条件的推断往往来自遥远的来源，通常是在格陵兰冰盖的高海拔地区，那里的气候条件完全不同。该项目将产生研究区域过去1500-2000年的多年代际（15-25年）分辨率记录。这将使用新的有机地球化学技术来完成，并将有助于校准和理解这些方法。这个项目将在一定程度上支持一位富有成效的年轻科学家在其职业生涯的形成阶段。它还将为研究生的培训提供支持。主要研究者（pi）将为马萨诸塞大学的一个暑期项目做出贡献，该项目旨在吸引12至18岁的女孩参与STEM领域，这些女孩大多来自代表性不足或低收入群体。pi和受资助的研究生将参加大学资助的初中和高中教师培训项目。最后，本科优等生经常参加co-PI实验室的活动。她希望与这个项目相关的研究能产生一些荣誉论文和高级项目。所有这些都有助于国家STEM劳动力的发展。该项目将继续与法国科学家建立国际合作关系。格陵兰岛北欧社区的消失及其与气候变化的潜在联系具有重大的人类利益，pi建议利用这一点。他们提议的外展活动包括为大众科学杂志撰写文章和开发一个项目网站。还预期PI将继续与当地印刷和电子媒体进行富有成效的互动。该项目将从格陵兰岛南部和西南部沿海地区的湖泊中获得过去2000年的高分辨率、定量的温度和水文记录，该地区与北大西洋更广泛的气候动态有着重要的联系。它还将揭示挪威人在该地区定居期间的气候波动。新的有机地球化学技术将用于过去的温度重建（支链甘油二烷基甘油四醚）和蒸发变化的估计（叶蜡氘同位素）随时间的变化。

The climate in southern Greenland is a key area for reconstructions of the North Atlantic Oscillation, a major pattern of northern hemisphere climate, and is also linked to Atlantic Meridional Overturning Circulation changes, an important oceanic process controlling north Atlantic climate, which recent studies suggest has been weaker over recent decades than at any time in the last 1000 years. This is also the region where Norse settlements were abandoned by the early-15th century; many questions still remain about the causative factors. Although climate change is often cited as the reason for settlement failure, this explanation rests on a very poorly constrained scientific foundation and other explanations have also been proposed. Inferences about climatic conditions in the region often have been derived from far distant sources, generally at high elevations on the Greenland Ice Sheet, where climatic conditions are completely different. This project will produce records with multidecadal (15-25 year) resolution from the study region, spanning the last 1500-2000 years. This will be accomplished using new organic geochemical techniques and will contribute to the calibration and understanding of these methodologies. This project will partially support a productive young scientist during the formative years of her career. It will also provide support for the training of a graduate student. The principal investigators (PIs) will contribute to a University of Massachusetts summer program designed to engage 12 to 18 year old girls, most from under-represented or low income groups, in STEM fields. The PIs and the supported graduate student will participate in university-sponsored middle and high school teacher training programs. Finally, undergraduate honors students often participate in the activities of co-PI's lab. She expects that a number of honors theses and senior projects will result from the research associated with this project. All of this contributes to development of the nation's STEM workforce. The project will continue an established international collaboration with French scientists. The disappearance of the Norse communities in Greenland and its potential linkage to climate change have significant human interest upon which the PIs propose to capitalize. Their proposed outreach activities include composing articles for popular science magazines and development of a project web site. It is also anticipated that the PI will continue his productive interactions with the local media, both print and electronic.This project will generate new high resolution, quantitative records of temperature and hydrology for the past 2,000 years from lakes in coastal regions of southern and southwestern Greenland, an area that has important links to the broader climate dynamics of the North Atlantic. It also will shed light on climatic fluctuations during the period of Norse settlement in the region. Novel organic geochemical techniques will be used for past temperature reconstruction (branched glycerol dialkyl glycerol tetraethers) and for estimates of changes in evaporation (leaf wax deuterium isotopes) over time.