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

职业：追逐冰山：量化格陵兰冰川峡湾的冰山运动和融化

• 批准号: 1552232
• 负责人: Joshua Roering
• 金额: $ 79.97万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-11-01 至 2021-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1552232&HistoricalAwards=false
• 关键词: CAREER; Chasing; icebergs; quantifying; iceberg

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.

格陵兰冰盖正在以液态水和固体冰的形式消失。固体冰以冰山的形式存在。这些冰山对峡湾水的分层和循环的影响，以及对邻近海洋淡水含量的影响，人们知之甚少。该项目将通过深入研究冰山融化和运动的过程，增进对冰山在峡湾和沿海海洋中的作用的了解。这些研究将包括现场观测和数值模拟实验。该项目将通过为一名研究生和一名博士后助理的培训提供支持，为该国STEM劳动力的发展做出贡献。为了加强向公众传播科学，将修改一门关于地球传播的课程，纳入新的多媒体方法。此外，该项目将允许PI扩展他之前与俄勒冈大学STEM核心项目的合作，以与当地一所中学合作开发以STEM为重点的课程。为了扩大对更广泛公众的接触，首席研究员将与一名科学历史学家合作，将存档数据转录成现代格式，供免费分发，联合发表公开演讲，在现有网站上添加内容，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)由于向冰川末端的海洋热传输增加，海底融化增加；(2)支撑冰川表面的冰川混杂减弱。峡湾是这两个过程之间的纽带，一方面是大范围的气候强迫(海洋和大气)，另一方面是格陵兰冰盖的可变性。然而，在大多数峡湾环流研究中，冰山融化这一关键过程在很大程度上被忽视了，这是因为对羽流驱动的环流的狭隘关注，以及获得现场观测的总体难度。这项提议旨在通过以高时间分辨率跟踪大型深龙骨冰山的水平和垂直运动来收集关于格陵兰-S峡湾冰山融化和运动的新观测。跟踪个别冰山，结合基于船只和无人机的调查，不仅可以量化冰山的融化速度，还可以量化冰山通过峡湾的移动，并最终扩散到大陆架和海洋内部。实地工作将在格陵兰相对研究较好的系统中进行，有可能迅速推广到其他系统。在海洋数值模拟的补充下，这些过程研究将能够评估水流参数在多大程度上捕捉到格陵兰水域中发生的融化过程。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，以及如何将其纳入可操作的冰山轨迹模型以及全球尺度气候模型提供坚实的基础。