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。彼得曼冰川消耗了格陵兰岛北部冰盖的很大一部分，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被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。在陆地、冰上和海上使用各种技术和方法，调查人员将绘制冰架前面和下面峡湾底部的地图；重建海洋条件及其在冰架变化中的作用；重建过去陆地冰川和浮冰架的覆盖范围；重建当地相对海平面。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一万年中对这些条件的反应的图景。在全新世早期，当地相对海平面比今天高100米以上（由于冰川消退导致地壳的滞后均衡反弹），但内陆冰盖相对于今天仍然很大，这一时期（陆地和海洋）的时间、程度、变化率和可变性将是关键的研究方向。研究人员将在与未来潜在影响相关的响应时间范围内（从几十年到几千年）处理对多个相互作用变量的动态响应。具体的研究问题包括：1)全新世记录下的气候变化对彼得曼冰架的影响有多敏感？2)陆架响应是独立的，还是与彼得曼冰川、海洋热条件或相对海平面（即静止深度）的变化有关？3)在全新世早期变暖、新冰期变冷和近期变暖的影响下，这些系统的变化率和变率是多少？该项目将支持几名年轻的调查人员，并将向他们提供船上和陆上培训经验。该项目包括重要的国际合作，以及来自美国以外国家的大量实物捐助。为项目增加价值的资源。计划的外展包括教师参与实地项目和在几个层次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.