EAR-PF: Uncovering climate-driven impacts on high-latitude aquifer-ocean exchange

Julia A.博士Guimond已获得NSF博士后研究金，在达尔豪西大学与美国地质调查局水循环分支合作研究沿海高纬度水文学。本研究将透过野外资料搜集与数值模拟分析，探讨高纬度地下水库与沿岸海洋的相互作用。在北极和亚北极地区，由于大气明显变暖，水流模式和储水量正在迅速变化。永久冻土融化引起的地下水流和含水层-海洋连通性的改变将对全球气候和高纬度沿海地区，包括海洋和淡水资源产生深远影响。由于海平面和海冰的变化以及永久冻土的分布，沿海系统特别容易受到气候引起的变化的影响。这项研究的主要目标是确定永久冻土区含水层-海洋交换的介导机制，以更好地了解这些过程如何在不断变化的气候条件下进行修改。这项研究的结果将有助于为土著社区和北方政府提供水和海洋资源管理以及气候适应战略的信息，并确定沿海水资源最容易受到气候变化引起的污染物动员的影响。Guimond博士进行的综合实地和建模研究旨在揭示高纬度永久冻土地区气候变化和含水层-海洋交换之间的反馈。结果将确定影响北极和亚北极海底地下水排放和盐水入侵的因素，并描述它们发生的空间和时间尺度，提高在不断变化的气候和水文条件下的预测能力。这项研究的结果将提高我们的知识：1）当今地下水排放到海洋的速率，2）控制永冻带地区含水层-海洋交换的过程，以及3）含水层-海洋交换对气候引起的变化（例如永冻带融化）的响应。本研究的田间部分将在Sanikiluaq（加拿大）和剑桥峡湾（加拿大巴芬岛）进行。将使用一套水文地质和地球化学实地工具和方法来评估当前的条件，如电导率、温度、深度记录仪和镭同位素。此外，将使用具有冻融、耦合表面-地下过程和变密度能力的数值水文模型来扩大对空间和时间的理解。通过这项综合研究阐明的过程和机制将促进新的概念和定量模型的发展，预测气候变化驱动的永久冻土融化和高纬度沿海系统的陆地-海水交换之间的反馈，可以为地下水管理政策提供信息。 PI将帮助开发一个网络研讨会系列，作为对更广泛的地球科学界关于北极和亚北极地区气候变化驱动问题的教育宣传。地球科学部的水文科学计划为该奖学金提供了共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. Julia A. Guimond has been granted an NSF EAR Postdoctoral Fellowship to study coastal high-latitude hydrology at Dalhousie University in collaboration with the Water Cycle Branch of the U.S. Geological Survey. Through field data collection and numerical modeling analyses, this research will investigate interactions between high-latitude groundwater reservoirs and the coastal ocean. In the Arctic and subarctic, water flow patterns and storage are rapidly changing due to pronounced atmospheric warming. Alterations in groundwater flow and aquifer-ocean connectivity due to permafrost thaw will have profound impacts on global climate and high-latitude coastal zones, including marine and freshwater resources. Coastal systems are particularly vulnerable to climate-induced change due to changes in sea level and sea ice in addition to permafrost distribution. The primary goal of this research is to identify the mechanisms mediating aquifer-ocean exchange in permafrost regions to better understand how these processes will be modified under changing climatic conditions. Results from this study will help inform water and marine-resource management and climate adaptation strategies for Indigenous communities and northern governments and identify where coastal water resources are most vulnerable to climate change-induced contamination mobilization.The integrated field and modeling study undertaken by Dr. Guimond aims to unravel the feedbacks between climate change and aquifer-ocean exchange in high-latitude permafrost regions. Results will identify the factors influencing Arctic and subarctic submarine groundwater discharge and saltwater intrusion and characterize the spatial and temporal scales over which they occur, improving predictive capacity under changing climatic and hydrologic conditions. Results of this study will enhance our knowledge of 1) present-day rates of groundwater discharge to the ocean, 2) processes controlling aquifer-ocean exchange in permafrost-bound regions, and 3) aquifer-ocean exchange response to climate-induced change (e.g. permafrost thaw). The field portion of this study will be conducted in Sanikiluaq, Canada and in Cambridge Fjord, Baffin Island, Canada. A suite of hydrogeological and geochemical field tools and methods will be used to assess present-day conditions, such as conductivity, temperature, depth loggers and radium isotopes. Also, numerical, hydrological models with freeze-thaw, coupled surface-subsurface processes, and variable density capabilities will be used to expand understanding in space and time. The processes and mechanisms elucidated through this integrated study will promote development of new conceptual and quantitative models that predict feedbacks between climate-change driven permafrost thaw and land-sea water exchange in high-latitude coastal systems that can inform groundwater management policies. The PI will help develop a cyber-seminar series as educational outreach to the broader geoscience community on climate-change driven issues in Arctic and subarctic regions. The Hydrological Science program in the Earth Science division provided co-funding for this fellowship.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.