Collaborative Research: Glacier-Ocean Coupling in a Large East Greenland Fjord

该奖项将支持格陵兰东部冰川-峡湾相互作用的研究。这项拟议研究的“智力价值”在于目前的理解，即格陵兰冰盖对海平面上升的贡献在过去七年中翻了一番以上，主要是因为许多冰川普遍且几乎同时加速，最终终止于深峡湾的潮水。了解冰川动态变化的原因，并预测其未来的轨迹是一个具有巨大科学和社会意义的话题。格陵兰峡湾提供了冰盖和海洋之间的密切联系，进而增加了观察到的格陵兰东南和西部海洋变暖是最近出口冰川动态变化的触发因素的可能性。在格陵兰岛东部进行的一项试点研究和在格陵兰西部进行的一项单独研究，分别在Helheim冰川和Jakobshavn Isbræ附近发现了温暖的海水，支持了海洋变暖引发它们加速的假设。虽然耐人寻味，但仅有格陵兰峡湾的温暖水域并不足以得出海洋正在调节冰川动态的结论。对这一假设的检验需要对冰川/峡湾相互作用有更详细的了解，而不是利用目前有限的数据量。这项研究将通过一项为期两年的密集实地项目，通过调查格陵兰岛东部一个典型的冰川-峡湾系统(Sermilik Fjord和Helheim Glacier)的冰川-海洋相互作用来填补这一空白。通过夏季调查和全年系泊仪器，将绘制出峡湾在潮汐到年的时间尺度上的环流和性质，并将量化峡湾外的液态淡水通量。与格陵兰海洋生物学家的合作将允许使用标记海豹获取峡湾以外地区的重要海洋数据。GPS方法和遥感将使人们能够在海湾环流变化的背景下研究赫尔海姆冰川流动行为的变化。卫星遥感和对大型冰山的实地跟踪将提供对淡水固体出口及其可变性的估计。这项拟议的研究有许多“更广泛的影响”。这很可能是下一代冰盖模型的重要组成部分，这些模型寻求预测格陵兰冰盖的演变和未来海平面上升的速度。该项目汇集了一个跨学科的研究小组，让两名初级科学家开始他们的职业生涯，并启动了与格陵兰科学家的国际合作。一名研究生将接受冰川学和物理海洋学方面的培训，以满足社会对冰盖-海洋相互作用领域专家的需求。实地考察利用当地船只，并高度依赖曾航行于塞米利克峡湾的几代当地猎人的知识，从而促进了当地社区与外国科学家之间的双向交流。一份总结海洋-冰川测量结果的非技术性报告将分发给当地社区，因为当地社区容易受到快速环境变化的影响，影响其主要自然资源。

This award will support a study of glacier-fjord interactions in east Greenland. The 'Intellectual Merit' of the proposed study lies in the current understanding that the contribution of the Greenland Ice Sheet to sea level rise more than doubled in the last seven years, mostly because of a widespread and nearly simultaneous acceleration of many glaciers that terminate at tidewater in deep fjords. Understanding the causes of changes in glacier dynamics, and predicting their future trajectories is a topic of enormous scientific and societal importance. The Greenland fjords provide an intimate connection between the ice sheet and the ocean and, in turn, raise the possibility that the observed warming of the ocean around southeast and western Greenland was the trigger for recent changes in outlet glacier dynamics. A pilot study conducted by the PIs in east Greenland, and a separate study in west Greenland, found warm ocean waters in the proximity of Helheim Glacier and Jakobshavn Isbræ, respectively, supporting the hypothesis that their acceleration was triggered by ocean warming. While intriguing, the presence of warm waters in Greenland's fjords alone is not enough to conclude that the ocean is modulating glacier dynamics. A test of this hypothesis requires a more detailed understanding of glacier/fjord interactions than is possible with the limited amount of data currently available. This study will fill this gap by investigating glacier-ocean interactions in a typical glacier-fjord system in East Greenland (Sermilik Fjord and Helheim Glacier) through an intensive two-year field program. Through summer surveys and year-round moored instruments, the circulation and properties of the fjord on tidal to yearly time-scales will be mapped, and the liquid fresh water flux out of the fjord will be quantified. A collaboration with Greenlandic marine biologists will allow important ocean data in the region outside the fjord to be obtained using tagged seals. GPS methods and remote sensing will allow changes in the flow behavior of Helheim Glacier to be examined in the context of changing fjord circulation. Satellite remote sensing and field tracking of large icebergs will provide estimates of the solid export of fresh water and its variability. The proposed study has numerous 'Broader Impacts'. The are likely to be a significant component of next-generation ice sheet models seeking to predict the evolution of the Greenland Ice Sheet and future rates of sea level rise. The project brings together an inter-disciplinary group of investigators, involves two junior scientists embarking on their careers, and initiates an international collaboration with Greenlandic scientists. A graduate student will be trained in glaciology and physical oceanography, contributing to society's need for experts in the area of ice sheet-ocean interactions. The fieldwork utilizes local vessels and relies strongly on the knowledge of generations of local hunters who have navigated Sermilik Fjord, thus fostering a two-way exchange between the local community and foreign scientists. A non-technical report summarizing the findings of ocean-glacier measurements will distributed in the local community, which is vulnerable to rapid environmental changes affecting its primary natural resource.