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

这项提议旨在钻探、分析和解释格陵兰东北海岸的伦兰冰帽的新冰芯。该项目是来自美国和丹麦大学冰与气候中心的科学家合作的项目。哥本哈根大学和德国阿尔弗雷德·韦格纳研究所。这里描述的美国的努力将集中在气体浓度和气体同位素(宾夕法尼亚州立大学的播种者)和冰的同位素(怀特，科罗拉多州)。丹麦的合作伙伴还将专注于冰和气体组成的稳定同位素以及高分辨率化学。德国合作伙伴将重点研究冰层的物理属性、线扫描和介电属性，以调查推动积雪致密化和冰芯年龄模型开发的因素。冰芯将在这一国际框架内进行回收和处理。考虑到伦兰冰盖包含的冰甚至比伊米亚冰盖更古老的明显可能性，CRESIS小组将在大学进行一次极高分辨率的无线电回声探测(RES)任务。2014年夏天，在堪萨斯州的伦兰冰盖上空进行了一次实地考察，以帮助指导2015年钻探项目的选址工作。伦兰是冰芯的重要位置，因为它很冷(罕见的融化层)，受地形限制，不能显著改变海拔，含有上一次冰川时期(可能还有伊米亚时期)的冰，并且没有被主要的格陵兰冰盖淹没。没有海拔变化意味着Renland的同位素温度和总空气含量记录可以作为气候标准，用于比较其他格陵兰冰芯。伦兰冰盖约有400米厚，因此不包含易碎的冰。这些特性将使在绘制和约束格陵兰气候条件方面取得重大科学进展，特别是在全新世。格陵兰其他冰芯中出现的脆性冰限制了我们重建高分辨率气候记录的能力，因为岩芯质量很差。Renland冰芯将提供重建整个全新世温室气体记录、火山活动、生物质燃烧事件以及关键反馈机制(如海冰范围)的手段。该项目的主要目标是：1)将格陵兰最近在过去十年中出现的迅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)提供从格陵兰核心到全新世的高质量气体记录，以检验有关早期人类活动可能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耦合的超高分辨率同位素温度记录，以及该区域有望追溯到最后间冰期的气候历史。该项目将提供重要数据，让公众和政策制定者了解地球气候以及气候变化的原因。该项目建议将格陵兰东部海冰的记录以及气候记录放在自然变化的背景下，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.