Collaborative Research: Petermann Gletscher, Greenland - Paleoceanography and Paleoclimatology

该项目将采用多学科方法来了解格陵兰北部彼得曼冰川过去对气候变化的反应。彼得曼冰川排干了格陵兰北部冰盖的很大一部分，并终止于一个对冰与海洋相互作用敏感的大型浮动冰架。过去十年的冰川消退打开了通往峡湾的通道，并为了解以前被冰架覆盖的区域下的沉积过程和校准过去冰架变化的重建提供了机会。使用陆地、冰层和海洋上的各种技术和方法，调查人员将绘制冰架前面和下面的峡湾底部的地图；重建海洋状况及其在冰架随时间变化中的作用；重建冰川过去在陆地和浮动冰架上的范围；以及重建当地的相对海平面。这些努力将全面了解过去10,000年来彼得曼冰川的气候条件和对这些条件的响应。人们最感兴趣的将是全新世早期的时间、程度、变化速度和变化(陆地和海洋上)，当时当地相对海平面比今天高100米以上(由于地壳对冰川消融的滞后均衡反弹)，但内陆冰盖与今天相比仍然很大。研究人员将研究与未来潜在影响相关的一系列响应时间(从数万年到数千年)对多个相互作用变量的动态响应。具体的研究问题包括：1)彼得曼冰架范围对全新世内记录的气候变化有多敏感？2)陆架响应独立于或与地面彼得曼冰川、海洋热条件或相对海平面(即海床深度)的变化无关或相关？3)这些系统对早期全新世变暖、新冰川冷却和最近变暖的响应速度和变异性有多大？该项目将支持几名年轻的调查人员，并将为他们提供舰载和陆基培训经验。该项目包括重要的国际合作，来自非美国来源的大量实物捐助为该项目增加了价值。计划的外展包括教师参与实地方案和在几个层面上有意义的课堂参与。

This project will take a multi-disciplinary approach to understanding the response of Petermann Glacier in northern Greenland to climate change in the past. Petermann Glacier drains a significant fraction of the northern Greenland ice sheet and terminates in a large floating ice shelf that is sensitive to ice-ocean interactions. Ice retreat over the last decade opens access to the fjord and presents an opportunity to understand sedimentation processes under the area previously covered by ice shelf and to calibrate reconstructions of past ice shelf variations. Using a variety of technologies and approaches on land, ice, and at sea, the investigators will map the bottom of the fjord in front of and under the ice shelf; reconstruct ocean conditions and their role in ice shelf variations through time; reconstruct the past extent of the glacier on land and the floating ice shelf; and reconstruct local relative sea level. Together these efforts will create a comprehensive picture of the climate conditions and response of the Petermann Glacier to these conditions over the last 10,000 years.Of key interest will be the timing, extent, rates of change, and variability (on land and in the sea) during the early Holocene when local relative sea level was over 100 meters higher than today (due to lagging isostatic rebound of the crust in response to deglaciation), but the inland ice sheet was still large relative to today. The investigators will address dynamic responses to multiple interacting variables over a range of response times (from tens to thousands of years) relevant to potential future impacts. Specific research questions include: 1) How sensitive is Petermann ice shelf extent to documented climate changes within the Holocene? 2) Is shelf response independent of, or linked to, variations in the grounded Petermann Glacier, ocean thermal conditions, or relative sea level (i.e., sill depth)? 3) What are the rates of change and variability of these systems in response to early Holocene warming, Neoglacial cooling, and recent warming? The project will support several young investigators and will provide them with both ship and land-based training experiences. The project includes significant international collaborations, with substantial in-kind contributions from non-U.S. sources that add value to the project. Planned outreach includes teacher participation in the field program and meaningful classroom involvement at several levels.