Inter-Hemispheric Climate Teleconnections in response to Massive Iceberg Discharge in the North Atlantic

世界一个地区的气候变化往往与世界另一个地区的变化联系在一起。例如，在几百年的时间尺度上，粗略的尺度代理表明，全球北大西洋地区的温度可能会发生变化，而南大西洋地区的温度可能会以相反的符号变化。这种“两极拉锯”的模型引发了信息通过大气或海洋的远距离传输(远程连接)。这项拟议的工作将利用格陵兰岛和南极洲的冰芯记录，研究在所谓的海因里希事件期间，海洋和大气遥相关在连接两个半球方面的相对作用。海因里希事件是指在上一个冰河时代反复发生的大规模冰山排放到北大西洋的事件。这项工作将帮助气候科学家了解发生在时间尺度上的动态变化，这些时间尺度比气象站的观测记录长得多。该项目还将有助于STEM劳动力的发展。它将为一位职业生涯早期的科学家在其职业生涯的形成阶段提供支持。它将为一名或多名本科实验室技术人员提供支持，并通过其他来源支持本科生参与研究。它将包括面向当地中学生的STEM外联活动和教师培训计划。这将导致维基百科上一系列关于古气候的条目。作为一项辅助效益，它将改进待研究的格陵兰冰芯的年代学。这将使两极之间的古气候记录更加同步，并促进过去气候研究的进展。拟议的工作将产生高分辨率、高精度的格陵兰(GISP2)冰芯甲烷、15N/14N分子氮比和空气含量的记录，以研究一些重要的古气候问题，特别是海因里希冰柱。拟议的工作安排在四个总体目标下：(1)探测海因里希事件对格陵兰气候的影响，并利用这些事件相对于观测到的南极快速变暖的时间来调查这些事件期间的半球间气候耦合模式是通过大气遥相关还是通过海洋遥相关；(2)实现GISP2和WAIS分水岭冰芯的极间甲烷同步，达到前所未有的百年分辨率，应用于研究半球间气候遥联和冰芯测年；(3)通过将氮同位素数据与由甲烷同步得出的独立三角洲年龄估计相结合，提供迄今为止最准确的格陵兰温度重建；以及(4)加强对空气含量作为冰盖高度指标的理解，并调查文献中未描述的丹斯加德-奥施格事件期间千年尺度空气含量变化的来源。该项目利用最近厘米尺度的WAIS甲烷分水岭记录所产生的独特的科学可能性来加强对格陵兰冰芯和极地气候连通性的解释

Changes in the climate of one part of the world can often be associated with changes in another part of the world. For example, on time scales of hundreds of years, coarse scale proxies indicate that the temperature of the North Atlantic region of the globe may change while the temperature of the South Atlantic region changes with the opposite sign. Models of this "bipolar seesaw" invoke the long-distance transmission (teleconnection) of information through the atmosphere or the ocean. The proposed work will use ice core records from Greenland and Antarctica to investigate the relative roles of oceanic and atmospheric teleconnections in coupling both hemispheres during so-called "Heinrich events" - massive discharges of icebergs into the North Atlantic that happed repeatedly during the last ice age. The work will help climate scientists understand dynamical changes that occur on times scales that are much longer than observational records from weather stations. The project will also contribute to development of the STEM workforce. It will provide support for an early-career scientist during the formative years of his career. It will provide support for one or more undergraduate laboratory technicians and entrain undergraduates, supported through other sources, into the research. It will include STEM outreach to local middle school students and a teacher training program. It will result in a series of Wikipedia entries concerning paleoclimate. As an ancillary benefit, it will improve the chronology of the Greenland ice core to be studied. This will allow greater synchronization of paleoclimate records between the two poles and facilitate progress in the study of past climates.The proposed work will generate high-resolution, high-precision records of Greenland (GISP2) ice core methane, 15N/14N ratio of molecular nitrogen, and air content for the period of 14-51 ka before present, to investigate a number of important paleoclimatic questions with a special focus on Heinrich stadials. The proposed work is organized under four overarching goals: (1) to detect the impact of Heinrich events on Greenland climate, and use the timing of these events relative to observed rapid Antarctic warming to investigate whether the mode of interhemispheric climate coupling during these events is via an atmospheric or an oceanic teleconnection; (2) to achieve interpolar methane synchronization of the GISP2 and WAIS Divide ice cores at unprecedented centennial-scale resolution, with applications in studying interhemispheric climate teleconnections and ice core dating.; (3) to provide the most accurate Greenland temperature reconstruction to date by combining nitrogen isotope data with independent delta-age estimates derived from the methane synchronization; and (4) to improve understanding of air content as a proxy for ice sheet elevation, and investigate origin of millennial-scale air content variations during Dansgaard-Oeschger events not previously described in the literature. This project exploits the unique scientific possibilities arising from the recent centimeter-scale WAIS Divide methane record to enhance the interpretation of Greenland ice cores and inter-polar climate connectivity