Access of Atlantic Water to East Greenland glaciers

大西洋水进入东格陵兰冰川

• 批准号: 313916277
• 负责人: Professor Dr. Torsten Kanzow, Ph.D.
• 金额: --
• 依托单位: Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/313916277?language=en
• 关键词: Access; Atlantic; Water; East; Greenland

The Greenland Ice Sheet is losing mass at an accelerating rate, making it today one of the largest contributors to global sea level rise. Warming subsurface (intermediate) ocean waters of Atlantic origin interacting with marine terminating glaciers within fjords around Greenland are regarded an import driver of the retreating ice sheet. During the first phase of SPP ”Regional Sea Level Chance and Society” within our project OGreen79 we able to show based on successful in situ observations on the shelf of Northeast Greenland, that the floating ice tongue of the 79-North Glacier (79NG) is exposed all-year-round to a swift inflow of warm Atlantic Intermediate Water (AIW). Surprisingly, the inflow into the ice shelf cavity is hydraulically controlled by a topographic sill right at the glacier calving front, which was discovered during one of our expeditions. We also demonstrated that the dramatic, ongoing thinning of the ice tongue of the 79NG by 90 m on decadal time scales has been driven by AIW warming. In this follow-up proposal, A2Green, we follow up on the important findings made during the first phase. We now widen the view to investigate ocean-glacier interaction on a regional rather than a local scale. We propose to extend our investigations to the entire East Greenland shelf north of Denmark Strait where the presence of subsurface AIW - interacting with numerous marine terminating glaciers - represents a ubiquitous feature. What makes the area unique, is that the AIW found on the shelf is mainly supplied be a single source, namely the recirculation of Atlantic Water in Fram Strait. Overall, three objectives will be pursued, relevant for the understanding of ocean-ice sheet interaction. We will investigate i. the multiannual large-scale ocean connections of the AIW present on the East Greenland continental shelf, ii. the role of shelf and shelf edge processes for AIW variability on the continental shelf, and iii. near-coastal, topographic control on time variable AIW inflows toward two different ocean-glacier systems. The 79NG - being located relatively close to the recirculation in Fram Strait - will remain an important focus. In addition, Scoresby Sound -located away from Fram Strait near the southern boundary of our work domain - will represent a new focus. One of the largest East Greenland glaciers, the Daugaard Jensen Glacier, terminates into the Scoresby Sound fjord system. The investigations will be achieved by analyzing both historical and active mooring time series in Fram Strait and on the shelf of East Greenland together with hydrographic data sets. High resolution simulation relying on an ocean-sea ice general circulation model will be applied to put the results into a larger spatial and temporal context.

格陵兰冰盖正在加速失去质量，使其成为今天全球海平面上升的最大贡献者之一。来自大西洋的暖化次表层（中层）海洋沃茨与格陵兰岛周围峡湾内的海洋终止冰川相互作用，被认为是冰盖退缩的输入驱动力。在我们的项目OGreen 79中的SPP“区域海平面机会和社会”的第一阶段，我们能够基于对格陵兰东北部大陆架的成功原位观测表明，79北冰川（79 NG）的浮冰舌全年暴露于温暖的大西洋中层水（AIW）的快速流入。令人惊讶的是，流入冰架空腔的水流是由冰川崩解前沿的地形岩床控制的，这是我们在一次探险中发现的。 我们还证明，在十年时间尺度上，79 NG冰舌急剧、持续变薄90 m是由AIW变暖驱动的。在这份名为A2 Green的后续提案中，我们对第一阶段的重要发现进行了跟进。我们现在扩大视野，在区域而不是局部尺度上研究海洋-冰川相互作用。我们建议将我们的调查扩展到整个东格陵兰大陆架北部的丹麦海峡的存在下AIW -与众多的海洋终止冰川相互作用-代表了一个无处不在的功能。该地区的独特之处在于，大陆架上发现的AIW主要由单一来源提供，即弗拉姆海峡的大西洋水再循环。总的来说，将追求三个目标，相关的海洋冰盖的相互作用的理解。 我们会调查的。多年的大规模海洋连接的AIW目前在东格陵兰大陆架，二。大陆架上AIW变化的大陆架和大陆架边缘过程的作用，iii.近海岸，地形控制的时间变量AIW流入两个不同的海洋冰川系统。79 NG位于相对靠近弗拉姆海峡的回流区，将仍然是一个重要的焦点。 此外，斯科尔斯比湾-位于远离弗拉姆海峡附近的南部边界，我们的工作领域-将代表一个新的重点。东格陵兰最大的冰川之一，道加德詹森冰川，终止于斯科尔斯比峡湾系统。调查将通过分析弗拉姆海峡和东格陵兰大陆架的历史和活动系泊时间序列以及水文数据集来完成。将采用依靠海洋-海冰环流模式的高分辨率模拟，以便将结果纳入更大的空间和时间范围。