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

北半球许多以海洋为终点的冰川最近和正在持续消退，这是海平面上升的重要原因。它是由冰-海洋界面上发生的鲜为人知的过程驱动的，例如冰下向海洋排放、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，需要创新的实地技术和谨慎的选址。该项目将通过在阿拉斯加州勒孔特冰川的全面实地活动，并辅之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。现场非常理想，因为它跨越了从日常到季节性的各种强制措施，而且接近终点的峡湾环境全年都是可以进入的。一个成功的项目将为预测未来海平面上升的贡献提供一个独特的数据集和改进的模型。这个跨学科项目位于冰川学和海洋学领域的交界处，为一个以本科生为主的机构(阿拉斯加东南大学)的一名职业早期首席研究员(Amundson)和俄勒冈大学的另一名早期职业首席研究员提供支持。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的大学的互动，将促进额外的劳动力发展。PI团队将从当地一所阿拉斯加高中挑选学生参与实地工作的方方面面，并与学校接触，将他们的观察融入课程。该项目还将为培训两名研究生和一名博士后学者提供支持。相关的指导计划非常好。会否利用私人投资推广计划，加强与市民大众的接触？国内机构？活动。私人投资机构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，以及对能够接触到广泛公众的解释性护林员的培训。最后，他们将编写一本小册子，介绍他们的工作，以进一步加强他们的公众出行。该项目将开发一种羽流的参数化，该羽流由冰川下的排放驱动，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认可的目标。这将通过开展三次密集的实地行动来实现。用载人船和自主船直接采集上升羽流的样本，2.测量羽流对近末端峡湾环流的下游影响，3。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。将在整个项目期间监测冰下流量和冰川峡湾周围的水性质，以提供信息。对于密集的实地战役来说，这是重要的背景，安迪。湍流分辨流体动力羽流模型要探索的参数空间范围。来自密集现场运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。后者将允许调查海底融化对季节性时间尺度上的冰川动力学的影响。

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.