Collaborative Research: Refining Long-term Climate Records from the Renland Ice Cap

该提案旨在钻探，分析和解释格陵兰岛东北海岸的Renland冰帽的新冰芯。这个项目是来自美国、丹麦哥本哈根大学冰与气候中心和德国阿尔弗雷德·韦格纳研究所的科学家们的合作项目。这里描述的美国的努力将集中在气体浓度和气体同位素（Sowers，宾夕法尼亚州立大学）和冰同位素（White，美国科罗拉多州）。丹麦合作伙伴还将关注冰和气体成分的稳定同位素，以及高分辨率化学。德国合作伙伴将专注于冰的物理特性、线扫描和介电特性，以研究驱动雪密度和冰芯年龄模型开发的因素。将在这一国际框架内回收和处理冰芯。考虑到Renland冰帽很有可能包含比Eemian更古老的冰，2014年夏天，堪萨斯大学的CReSIS小组将在Renland冰帽上空执行一个极高分辨率的无线电回波探测（RES）任务，以帮助指导2015年钻探项目的选址。Renland是冰芯的重要位置，因为它很冷（很少有融化层），受地形的限制，因此它不能显著改变海拔，包含最后一个冰期（可能还有Eemian期）的冰，并且没有被格陵兰岛的主要冰盖淹没。缺乏海拔变化意味着Renland的同位素温度和总空气含量记录可以用作气候标准，与其他格陵兰冰芯进行比较。伦兰冰盖约有400米厚，因此不含易碎冰。这些特性将使在绘制和限制格陵兰岛总体气候条件方面取得重大的科学进展，特别是全新世。格陵兰岛其他冰芯中出现的脆性冰，由于冰芯质量差，限制了我们重建高分辨率气候记录的能力。Renland冰芯将提供重建温室气体记录、火山活动、生物质燃烧事件以及全新世海冰范围等关键反馈机制的手段。该项目的主要目标是：1)将过去十年来格陵兰岛的快速变暖与过去几个世纪的基线记录以及更广泛的全新世记录联系起来；2)从格陵兰岩心提供整个全新世的高质量气体记录，以验证早期人类活动如何影响温室气体组成的现有理论；3)提供与格陵兰东部附近海冰紧密相关的超高分辨率同位素温度记录，以及该地区的气候历史，希望可以追溯到最后一次间冰期。这个项目将提供重要的数据，让公众和政策制定者了解地球的气候以及导致气候变化的原因。该项目建议将格陵兰东部的海冰记录和气候记录放在自然变率的背景下，并进一步了解最近北极温度和海冰的快速变化。该项目将支持研究生和本科生。

This proposal seeks to drill, analyze, and interpret a new ice core from the Renland Ice Cap on the north east coast of Greenland. The project is a collaborative venture between scientists from the U.S., Denmark's Center for Ice and Climate at the Univ. of Copenhagen and Germany's Alfred Wegner Institute. U.S. efforts described here will focus on gas concentrations and gas isotopes (Sowers, Penn State) and ice isotopes (White, U. Colorado). Danish partners will also focus on stable isotopes of ice and gas composition, as well as high-resolution chemistry. German partners will focus on physical properties of the ice, line scanning and dielectric properties to investigate the factors driving snow densification and ice core age model development. Ice cores will be retrieved and processed within this international framework. Given the distinct possibility that the Renland ice cap will contain ice even older than the Eemian, an extremely high resolution Radio Echo Sounding (RES) mission will be flown by the CReSIS group at the Univ. of Kansas over the Renland Ice Cap in the summer of 2014, in order to help guide site selection for the 2015 drill project. Renland is an important location for an ice core as it is cold (infrequent melt layers), constrained by topography so that it cannot significantly change in elevation, contains ice from the last glacial period (and possibly the Eemian period), and has not been overrun by the main Greenland ice sheet. The lack of elevation change means that Renland's isotopic temperature and total air content records can be used as climate standards against which to compare other Greenland ice cores. The Renland ice cap is about 400 meters thick so it does not contain brittle ice. These properties will allow significant scientific progress to be made in mapping out and constraining Greenland climatic conditions in general, but especially for the Holocene. The occurrence of brittle ice in other Greenland ice cores has limited our ability to reconstruct high-resolution climate records due to poor core quality. The Renland ice core will provide the means of reconstructing greenhouse gas records, volcanic activity, biomass burning events, as well as key feedback mechanisms such as sea ice extent throughout the Holocene. Primary objectives of this project are: 1) link the recent, rapid warming seen in Greenland over the past decade to the baseline record of the past few centuries, as well as the broader Holocene record; 2) provide high-quality gas records throughout the Holocene from a Greenland core to test current theories about the how early human activity may have impacted the greenhouse gas composition; 3) provide an ultra-high resolution isotopic temperature record that is tightly coupled to sea ice near eastern Greenland, as well as a history of climate in this region hopefully extending back into the last interglacial period. This project will provide important data to inform the public, and policy makers, about the earth's climate and what causes changes in that climate. This project proposes to place both the records of sea ice off eastern Greenland, as well as the climate record, into the context of natural variability, and further understanding of recent rapid changes in Arctic temperatures and sea ice. The project will support graduate and undergraduate students.