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，北大西洋涛动是北方半球气候的主要模式，格陵兰岛南部的气候也与大西洋经向翻转环流变化有关，大西洋经向翻转环流变化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，最近几十年来，它比过去1000年的任何时候都要弱。 这也是挪威人定居点在世纪早期被遗弃的地区;许多关于成因的问题仍然存在。虽然气候变化经常被引用为定居失败的原因，但这种解释依赖于一个非常不受约束的科学基础，也有人提出了其他解释。 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年的数十年（15-25年）分辨率的记录。 这将使用新的有机地球化学技术来完成，并将有助于这些方法的校准和理解。 该项目将部分支持一个富有成效的年轻科学家在她的职业生涯的形成期。 它还将为一名研究生的培训提供支助。 主要研究者（PI）将为马萨诸塞州大学的暑期项目做出贡献，该项目旨在吸引12至18岁的女孩，大多数来自代表性不足或低收入群体，在STEM领域。 PI和支持的研究生将参加大学赞助的初中和高中教师培训计划。 最后，本科荣誉学生经常参加co-PI实验室的活动。 她预计，一些荣誉论文和高级项目将导致与此项目相关的研究。 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进行既定的国际合作。 格陵兰岛挪威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建议利用这些利益。 他们提议的推广活动包括为科普杂志撰写文章和开发一个项目网站。 预计该项目还将继续与当地印刷和电子媒体进行富有成效的互动，该项目将产生格陵兰南部和西南部沿海地区湖泊过去2,000年来温度和水文的新的高分辨率定量记录，该地区与北大西洋更广泛的气候动态有重要联系。 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（叶蜡氘同位素）随时间的变化估计。

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.