Collaborative Research: Impact of subglacial discharge on turbulent plume dynamics and ocean-glacier heat and mass transfer

合作研究：冰下排放对湍流羽流动力学和海洋-冰川传热传质的影响

• 批准号: 1504288
• 负责人: Jason Amundson
• 金额: $ 49.85万
• 依托单位: University of Alaska Southeast Juneau Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1504288&HistoricalAwards=false
• 关键词: Collaborative; Research; Impact; subglacial; discharge

Recent and on-going retreat of many Northern hemisphere marine-terminating glaciers is contributing significantly to sea level rise. It is driven by poorly understood processes occurring at the ice-ocean interface, such as subglacial discharge into the ocean, turbulent plume dynamics, submarine melting, and iceberg calving. These processes are (1) inherently interdisciplinary, requiring expertise in both glaciology and oceanography and (2) difficult to observe, requiring innovative field techniques and careful site selection. This project will address the relationship between subglacial discharge, turbulent plume dynamics, and submarine melting through a comprehensive field campaign at LeConte Glacier, Alaska, supplemented by a state-of-the-art modeling effort. The field site is ideal because it spans a wide range of forcings on daily to seasonal time scales and because the near-terminus fjord environment is accessible year round. A successful project will provide a unique data set and improved models for projecting contributions to future sea level rise.This interdisciplinary project, at the interface of the the fields of glaciology and oceanography, provides support for an early-career principal investigator (PI) (Amundson) from a predominantly undergraduate institution (University of Alaska Southeast) and an additional early career PI at University of Oregon. More mature PIs at Oregon State University and University of Alaska Fairbanks Campus will mentor the younger team members, promoting workforce development. Additional workforce development will be promoted through interaction with high school students and at the participating universities. The team of PIs will entrain select students from a local Alaska high school to participate in aspects of the field work and engage with the school to integrate their observations into the curriculum. The project will also provide support for the training two graduate students and a post-doctoral scholar. The associated mentoring plan is very good. Outreach to the general public will be enhanced by leveraging the PIs? home institutions? activities. The PIs will continue established interactions with the National Park Service and the US Forest Service. These include public lectures, as well as training for interpretive rangers who can reach a broad cross-cut of the public. Finally, they will develop a brochure concerning their work to further enhance their public outreach.This project will develop a parameterization of a plume, driven by subglacial discharge, as it interacts with the face of a marine-terminating glacier. This is a goal that has been endorsed by the international community. It will be accomplished by conducting three intensive field campaigns toi. sample the upwelling plume directly with manned and autonomous vessels,ii. measure the downstream impact of the plume on near-terminus fjord circulation,iii. determine subglacial discharge and submarine melt rates, andiv. survey associated changes in glacier terminus dynamics.Subglacial discharge and ambient water properties in the proglacial fjord will be monitored throughout the project in order to providei. important context for the intensive field campaigns, andii. a range of parameter space to be explored by a turbulence-resolving hydrodynamic plume model.Data from the intensive field campaigns will be used to validate the plume model, which will then be used to explore the wider range of parameter space that is provided by long-term measurements. The latter will allow investigation of the impact of submarine melting on glacier dynamics over seasonal timescales.

北半球许多海洋终止冰川最近和持续的退缩对海平面上升做出了重大贡献。 它是由冰-洋界面发生的人们知之甚少的过程驱动的，例如冰下向海洋的排放、湍流羽流动力学、海底融化和冰山崩解。这些过程（1）本质上是跨学科的，需要冰川学和海洋学方面的专业知识；（2）难以观察，需要创新的现场技术和仔细的地点选择。该项目将通过在阿拉斯加勒孔特冰川进行全面的现场活动，并辅以最先进的建模工作，来解决冰下放电、湍流羽流动力学和海底融化之间的关系。该现场地点非常理想，因为它涵盖了日常到季节时间尺度上的各种强迫，而且因为近端峡湾环境全年均可进入。 一个成功的项目将提供独特的数据集和改进的模型，用于预测对未来海平面上升的贡献。这个跨学科项目位于冰川学和海洋学领域的交叉点，为早期职业首席研究员（PI）提供支持（ Amundson）来自一所以本科为主的院校（阿拉斯加东南大学），也是俄勒冈大学的一名早期职业 PI。 俄勒冈州立大学和阿拉斯加大学费尔班克斯校区更成熟的 PI 将指导年轻的团队成员，促进劳动力发展。 通过与高中生和参与大学的互动，将促进额外的劳动力发展。 PI 团队将邀请阿拉斯加当地高中的精选学生参与实地工作的各个方面，并与学校合作，将他们的观察结果纳入课程中。 该项目还将为培养两名研究生和一名博士后提供支持。 相关的指导计划非常好。 通过利用 PI 可以加强对公众的宣传吗？国内机构？活动。 PI 将继续与国家公园管理局和美国林业局建立互动关系。 其中包括公开讲座，以及对能够广泛接触公众的解释护林员的培训。 最后，他们将制作一本有关其工作的小册子，以进一步加强其公众宣传。该项目将开发由冰下放电驱动的羽流参数化，因为它与海洋终止冰川的表面相互作用。 这是得到国际社会认可的目标。 这将通过开展三场密集的实地活动来完成。使用有人驾驶和自主船只直接对上升流羽流进行采样，ii.测量羽流对近端峡湾环流的下游影响，iii。确定冰下放电和海底融化速率，以及调查冰川终点动态的相关变化。在整个项目中将监测前冰川峡湾的冰下排放和环境水特性，以便提供信息。密集实地活动的重要背景，andii。湍流解析流体动力学羽流模型要探索的一系列参数空间。来自密集现场活动的数据将用于验证羽流模型，然后将其用于探索长期提供的更广泛的参数空间- 术语测量。后者将允许研究海底融化对季节性时间尺度上冰川动态的影响。