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

Julia A. Guimond博士获得了美国国家科学基金会EAR博士后奖学金，与美国地质调查局水循环部门合作，在达尔豪斯大学研究沿海高纬度水文学。本研究将通过野外数据收集和数值模拟分析，探讨高纬度地下水库与沿海海洋之间的相互作用。在北极和亚北极，由于明显的大气变暖，水流模式和储水量正在迅速变化。永久冻土融化导致的地下水流量和含水层-海洋连通性的变化将对全球气候和高纬度沿海地区产生深远影响，包括海洋和淡水资源。除了永久冻土分布外，由于海平面和海冰的变化，沿海系统特别容易受到气候引起的变化的影响。本研究的主要目标是确定永久冻土区含水层-海洋交换的调节机制，以更好地了解这些过程如何在不断变化的气候条件下被修改。这项研究的结果将有助于为土著社区和北方政府的水和海洋资源管理和气候适应战略提供信息，并确定哪些沿海水资源最容易受到气候变化引起的污染动员的影响。吉蒙德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区气候变化与含水层-海洋交换之间的反馈关系。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，并描述它们发生的时空尺度，提高在不断变化的气候和水文条件下的预测能力。本研究的结果将增强我们对以下方面的认识：1)当前向海洋排放地下水的速率；2)控制永久冻土区含水层-海洋交换的过程；3)含水层-海洋交换对气候引起的变化（如永久冻土融化）的响应。本研究的实地部分将在加拿大的Sanikiluaq和加拿大巴芬岛的剑桥峡湾进行。将使用一套水文地质和地球化学现场工具和方法来评估当前的条件，如电导率、温度、深度记录器和镭同位素。此外，具有冻融、地表-地下耦合过程和变密度能力的数值水文模型将用于扩展在空间和时间上的理解。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，这些模型可以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，从而为地下水管理政策提供信息。PI将帮助开发一个网络系列研讨会，作为对北极和亚北极地区气候变化驱动问题的更广泛的地球科学社区的教育推广。地球科学部的水文科学项目为该奖学金提供了共同资金。该奖项反映了美国国家科学基金会的法定使命，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.