CAREER: Chasing icebergs: quantifying iceberg motion and melt in Greenland's glacial fjords

格陵兰冰盖上的物质以液态水和固态冰的形式流失。固体冰以冰山的形式出现。这些冰山对峡湾海水的分层和循环，以及对邻近海洋的淡水含量的影响，人们了解得很少。该项目将通过对冰山融化和移动的深入过程研究，提高对冰山在峡湾和沿海海洋中的作用的认识。这些研究将包括实地观察和数值模拟实验。该项目将通过为研究生和博士后助理的培训提供支持，为国家STEM劳动力的发展做出贡献。为了加强与公众的科学交流，我们将修改地理通讯课程，加入新的多媒体方法。此外，该项目将允许PI扩展他之前与俄勒冈大学STEM CORE项目的合作，与当地一所中学合作开展以STEM为重点的课程。为了加强与更广泛的公众的联系，首席研究员将与一位科学历史学家合作，将存档的数据转录成现代格式，以便自由分发，共同发表公开演讲，为现有的网站添加内容，并参加由他的机构组织的关于气候变化和土著人民的年度活动。格陵兰岛周围海洋-冰川相互作用研究的持续激增主要是为了提高我们对海洋环流在出口冰川变化中所起作用的理解。导致冰川加速和动态变薄的两个潜在机制是：(1)由于海洋向冰川末端的热输送增强，海底融化增加，以及(2)支撑冰川表面的冰凌变弱。峡湾是这两个过程之间的纽带，一方面是大尺度的气候强迫（海洋和大气），另一方面是格陵兰冰盖的变化。然而，在大多数峡湾环流研究中，由于对羽流驱动环流的狭隘关注，以及获得现场观测的总体困难，冰山融化这一关键过程在很大程度上被忽视了。该提案旨在收集关于格陵兰岛冰山融化和移动的新观测结果。通过在高时间分辨率下跟踪大型深龙骨冰山的水平和垂直运动来研究美国峡湾。对单个冰山的追踪，结合船只和无人机的调查，不仅可以量化冰山融化的速度，还可以量化冰山在峡湾的移动，并最终分散到大陆架上，进入内陆海洋。实地工作将在格陵兰研究相对充分的系统中进行，有可能迅速推广到其他系统。在数值海洋模拟的补充下，这些过程研究将能够评估当前参数化如何很好地捕捉格陵兰水域发生的融化过程。最终，这些结果将为更好地理解冰山运动和融化的时空图景以及如何将其纳入业务冰山轨迹模型以及全球尺度气候模型提供坚实的基础。

Mass is being lost from the Greenland Ice Sheet both in the form of liquid water and solid ice. The solid ice occurs in the form of icebergs. The influence of these icebergs on the stratification and circulation of water in fjords, as well as on the freshwater content of the adjacent ocean, is poorly understood. This project will improve understanding of the role of icebergs in fjords and the coastal ocean through intensive process studies on iceberg melt and movement. These studies will include both field observations and numerical modeling experiments. The project will contribute to the development of the nation's STEM workforce by providing support for the training of a graduate student and a post-doctoral associate. To enhance the communication of science to the general public, a course in Geo-communication will be modified to include new multi-media approaches. Additionally, the project will allow the PI to extend his prior collaborations with University of Oregon's STEM CORE program to work with a local middle school on STEM-focused curricula. To enhance outreach to the broader public, the principal investigator will collaborate with a science historian to transcribe archived data into modern format that will be freely distributed, co-deliver public talks, add content to an existing website, and participate in an annual event on Climate Change and Indigenous Peoples organized by his institution.The ongoing surge in ocean-glacier interactions studies around Greenland is motivated primarily to improve our understanding of the role ocean circulation plays in outlet glacier variability. Two potential mechanisms that lead to glacier acceleration and dynamic thinning are (1) increased submarine melting due to an enhanced ocean heat transport to the glacier termini, and (2) a weakening of the ice mélange that buttresses the glacier face. Fjords act as links between these two processes with the large-scale climate forcing on one hand (both oceanic and atmospheric) and the Greenland ice sheet variability on the other. However, one key process, iceberg melt, has been largely neglected in most fjord circulation studies due to a narrow focus on plume driven circulation, as well as the overall difficulty of obtaining in situ observations. This proposal aims to gather novel observations on iceberg melt and movement in Greenland?s fjords by tracking the horizontal and vertical motion of large, deep-keeled icebergs at high temporal resolution. Tracking individual icebergs, combined with ship- and drone-based surveys, will allow quantification not only of iceberg melt rates, but also of their movement through the fjord and eventual dispersal across the shelf and into the interior ocean. Fieldwork will be conducted in relatively well-studied systems in Greenland, with the potential for rapid generalization to other systems. Complemented by numerical ocean modeling, these process studies will enable assessment of how well current parameterizations capture the melt processes occurring in Greenland's waters. Ultimately, these results will provide a solid foundation for improving understanding of the spatial and temporal picture of iceberg motion and melt and how this can be incorporated into operational iceberg trajectory models, as well as global scale climate models.