SGER: High Resolution Radar Mapping of Ice Thickness and Near-Surface Layers in Northeast Greenland

SGER：格陵兰岛东北部冰厚和近地表层的高分辨率雷达测绘

• 批准号: 0608181
• 负责人: Claude Laird
• 金额: $ 2.49万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-15 至 2007-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0608181&HistoricalAwards=false
• 关键词: SGER; Resolution; Radar; Mapping; Ice

ABSTRACTLairdOPP-0608181The Principal Investigators propose to use two compact, wideband radars to map near -surface and deep internal ice layers around an ice core to be drilled on the 540 m thick, coastal Flade Isblink Ice Cap in NE Greenland in May - June, 2006. This work will be part of a collaborative, multi-national effort led by Danish researchers to characterize the relationship between climate change and the evolution of the ice caps and sea ice. The low-power radars, their antennas and a portable generator will be mounted on a Nansen sled and pulled behind a snowmobile in an approximately 9 km x 9 km grid centered on the core drill site to map accumulation rates, accumulation variability, thickness and flow properties across the dome. The two radar systems have already been developed and tested extensively in both Greenland and Antarctica and can be deployed without additional modifications.The proposal leverages additional logistical support provided by the University of Copenhagen team. All collaborators have agreed to share data sets. The costs for this project, such as equipment maintenance, data processing and analysis, and publication of results will be borne by the CReSIS (Center for Remote Sensing of Ice Sheets).Intellectual Merit Little is known about paleoclimatic change in northern Greenland andhow it is related to paleoclimatic change in the rest of Greenland. The scientific merit will be the exploration of this remote and little studied region with ground penetrating radar to provide input to, and validation of, high-resolution numerical models of ice sheet dynamicsand evolution for predicting climate change and sea - level rise. Ice core and radar studiesprovide a more complete picture of the evolution of the ice cap and the climate history of that region. Radar measurements are critical for extrapolating the internal structure and history of the ice laterally beyond the core site, which is effectively a point source on the ice cap,for use in ice sheet models. At the same time, ice core temperature and density measurements are necessary to convert the radar profiles from travel time into depth domain for accurate near - surface accumulation profiles and ECM (Electrical Conductivity Measurements) and depth/age profiles are required to provide ground truth for mapping deep isochrones due to volcanic activity. The radar profiles will also: 1) resolve ice sheet thickness and layer deformation, 2) expand on internal layer structure and ice flow properties, and 3) look at topographic effects on accumulation. With the aid of the accumulation profiles, the Principal Investigators hope to learn if the ice cap survived the early Holocene Climatic Optimum and why it is growing at a rate of about 50 cm/y when the mass balance of the ice sheet is slightly negative and thinning predominates in lower, coastal areas.Broader Impacts An electrical engineering graduate student will be directly involved in thisproject, both in the field and in the lab, assisting with radar operation, data analysis and visualization, linking radar data to glaciological issues addressed by this project. The research group currently has a strong outreach program and will leverage CReSIS resources to: 1) provide a journal and pictures for posting on our website, 2) develop a travelogue and course materials for K -12 students, and 3) present lectures on Flade Isblink activities for students at Haskell Indian Nations University. All ice core and radar data from this project will be submitted to NSIDC within one year after returning from the field.

主要研究人员建议使用两个紧凑的宽带雷达来绘制2006年5 - 6月在格陵兰岛东北部540 m厚的沿海Flade Isblink冰帽上钻取的冰芯周围的近地表和深层内部冰层。这项工作将是由丹麦研究人员领导的多国合作努力的一部分，以确定气候变化与冰盖和海冰演变之间的关系。 低功率雷达、其天线和便携式发电机将安装在南森雪橇上，并在以岩心钻探现场为中心的约9公里x9公里网格中由雪地车牵引，以绘制累积速率、累积变化、厚度和整个圆顶的流动特性。这两个雷达系统已经在格陵兰岛和南极洲进行了广泛的开发和测试，无需额外修改即可部署。该提案利用了哥本哈根大学团队提供的额外后勤支持。 所有合作者都同意分享数据集。该项目的费用，如设备维护，数据处理和分析，并公布结果将由CReSIS（中心遥感冰盖）。知识价值很少有人知道在格陵兰岛北方的古气候变化和它是如何与古气候变化在格陵兰岛的其余部分。其科学价值将是用探地雷达探测这一偏远和很少研究的地区，为预测气候变化和海平面上升的冰盖动态和演变的高分辨率数值模型提供投入和验证。冰芯和雷达研究提供了一个更完整的冰帽的演变和该地区的气候历史。雷达测量对于推断冰的内部结构和历史横向超出核心网站，这是有效的冰帽上的点源，用于冰盖模型是至关重要的。与此同时，冰芯温度和密度测量是必要的，以将雷达剖面从旅行时间转换到深度域，以获得准确的近地表积累剖面，并且需要ECM（电导率测量）和深度/年龄剖面，以提供绘制火山活动引起的深层等时线的地面实况。雷达剖面图还将：1）解决冰盖厚度和层变形，2）扩展内部层结构和冰流特性，3）查看地形对堆积的影响。在积累剖面的帮助下，主要研究人员希望了解冰盖是否在全新世早期气候最佳状态下幸存下来，以及为什么当冰盖的质量平衡略为负值且在较低的沿海地区主要变薄时，冰盖以约50厘米/年的速度增长。在实地和实验室，协助雷达操作、数据分析和可视化，将雷达数据与该项目所处理的冰川学问题联系起来。该研究小组目前有一个强大的外展计划，并将利用CReSIS资源：1）提供一个杂志和图片张贴在我们的网站上，2）开发一个游记和课程材料K-12学生，和3）目前讲座在哈斯克尔印度民族大学的学生弗拉德Isblink活动。本项目的所有冰芯和雷达数据将在从现场返回后一年内提交给NSIDC。