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

最近和正在进行的许多北半球海洋冰川的退缩正在对海平面上升作出重大贡献。它是由冰-海界面发生的鲜为人知的过程驱动的，例如冰下排放到海洋中，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的专业知识；(2)很难观察，需要创新的现场技术和仔细的选址。该项目将通过在阿拉斯加的勒孔特冰川进行全面的实地考察，并辅以最先进的建模工作，解决冰下流量、湍流羽流动力学和海底融化之间的关系。现场场地是理想的，因为它跨越了日常到季节性时间尺度的广泛强迫，因为近终点的峡湾环境全年都可以进入。一个成功的项目将为预测对未来海平面上升的贡献提供独特的数据集和改进的模型。这个跨学科的项目，在冰川学和海洋学领域的接口，提供了一个早期职业生涯的首席研究员（PI）（阿蒙森）从一个主要的本科机构（阿拉斯加东南大学）和一个额外的早期职业生涯的PI在俄勒冈大学。俄勒冈州立大学和阿拉斯加费尔班克斯大学校区更成熟的pi将指导年轻的团队成员，促进劳动力的发展。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团队将从阿拉斯加当地的一所高中选拔学生参加实地工作，并与学校合作，将他们的观察融入课程。该项目还将为培养2名研究生和1名博士后提供支持。相关的指导计划非常好。我们会善用“公共服务计划”，加强与市民的联系。家机构?活动。pi将继续与国家公园管理局和美国林务局建立互动关系。这些措施包括公开讲座，以及培训解说护林员，他们可以接触到广泛的公众。最后，他们将编写一份关于其工作的小册子，以进一步加强其公共宣传。这个项目将开发一个羽流的参数化，由冰下流量驱动，因为它与海洋终止冰川的表面相互作用。这是一个得到国际社会赞同的目标。它将通过开展三次密集的实地运动来完成。用有人驾驶和自动驾驶船只直接取样上涌羽流。测量羽流对峡湾近端环流的下游影响；确定冰下流量和海底融化速率。调查冰川末端动态的相关变化。在整个项目中，将监测冰下流量和原冰峡湾的环境水特性，以便提供。密集实地运动的重要背景，以及。紊流解析流体动力羽流模型有待探索的参数空间范围。来自密集的野外活动的数据将用于验证羽流模型，然后将用于探索由长期测量提供的更大范围的参数空间。后者将允许在季节性时间尺度上调查海底融化对冰川动态的影响。

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.