Collaborative Research: Petermann Gletscher, Greenland - Paleoceanography and Paleoclimatology

该项目将采取多学科方法，了解格陵兰北方的彼得曼冰川过去对气候变化的反应。彼得曼冰川排出了格陵兰岛北方冰盖的很大一部分，并终止于一个对冰-海相互作用敏感的大型浮动冰架。过去十年来的冰退缩打开了通往峡湾的通道，并提供了一个机会来了解以前由冰架覆盖的区域下的沉积过程，并校准过去冰架变化的重建。研究人员将利用陆地、冰和海上的各种技术和方法，绘制冰架前方和下方的峡湾底部;重建海洋条件及其在冰架变化中的作用;重建陆地和浮冰架上冰川的过去范围;重建当地的相对海平面。这些努力将共同创造一个全面的气候条件和彼得曼冰川在过去10,000年对这些条件的反应的图片。关键的兴趣将是时间，程度，变化率，和可变性（陆地和海洋）在全新世早期，当地的相对海平面比今天高出100米以上（由于地壳对冰川消退的滞后均衡反弹），但内陆冰盖相对于今天仍然很大。研究人员将讨论在与未来潜在影响相关的一系列反应时间（从几十年到几千年）内对多个相互作用的变量的动态反应。具体的研究问题包括：1）彼得曼冰架范围对全新世气候变化的敏感性如何？2)大陆架响应是否独立于或与彼得曼冰川、海洋热条件或相对海平面（即，窗台深度）？3)这些系统对全新世早期变暖、新冰期变冷和近期变暖的响应率和变化率是多少？该项目将支持几名年轻的调查人员，并为他们提供船上和陆地培训经验。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。计划的推广活动包括教师参与实地项目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.