RII Track-4:NSF: From the Ground Up to the Air Above Coastal Dunes: How Groundwater and Evaporation Affect the Mechanism of Wind Erosion

沿海沙丘是保护沿海地区免受风暴和海平面上升影响、为动植物物种提供栖息地并通过旅游业和保护服务为沿海人口创造收入的基本特征。然而，各种应激源，包括风蚀和人类活动，限制了它们作为保护屏障的能力。尽管在模拟和预测海岸沙丘演变方面取得了进展，但尚未解决的机制及其相互作用限制了侵蚀预测模型的准确性和可靠性。该项目旨在研究这些尚未解决的机制，特别是研究地下水抬高和蒸发对风蚀机制和沿海沙丘演变的影响，这些尚未深入探索。该项目将使用配备高精度和坚固仪器的尖端风洞和基于计算机的模型来连接地下流动和上面的空气。这项研究的结果将为深入了解沿海沙丘风蚀的大气和地下现象之间的联系提供洞察力。这些发现可以帮助识别沿海沙丘的脆弱地带，减少灾害，并提高沿海人口的适应能力。此外，研究结果可以通过分析植被和水分含量调节机制的影响来指导侵蚀控制技术的发展。这项研究基础设施改善Track-4 EPSCoR研究人员(RII Track-4)项目将为缅因州大学的一名助理教授提供奖学金，并为一名研究生提供培训。这项工作将与佛罗里达大学的研究人员合作进行。该项目基于这样一个基本假设，即沿海沙丘的风蚀机制受到从沙丘蒸发到风流的水与从地下水位到地表的毛细上升再补给之间的竞争，从而影响其可蚀性。这是一个开创性的概念，因为它首次考虑了地下水高程和毛管上升对沿海沙丘可蚀性的作用。这一假设将通过一系列新颖的风洞测试进行实验验证，这些测试将在佛罗里达大学的NSF边界层风洞设施进行，该设施是国家危险工程研究基础设施(NHERI)的一部分。此外，基于求解沙子下表面和上面空气中水的质量守恒的分析模型将提供验证和推广使用有限元方法在大范围和长期条件下的风洞实验结果的手段。这项研究的结果将提供对将大气和地下现象与沿海沙丘风蚀联系起来的过程的见解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Coastal dunes are an essential feature that protects coastal areas from storms and sea-level rise, provides habitat for plant and animal species, and generates income for coastal populations through tourism and protective services. However, various stressors, including wind erosion and human activities, limit their capacity as protective barriers. Despite advancements in modeling and forecasting coastal dune evolution, unresolved mechanisms and their interactions limit the accuracy and reliability of erosion predictive models. This project aims to investigate those unresolved mechanisms, particularly studying the effects of groundwater elevation and evaporation on the mechanisms of wind erosion and the evolution of coastal dunes, which have yet to be thoroughly explored. The project will use a cutting-edge wind tunnel outfitted with high-precision and robust instrumentation and a computer-based model to link subsurface flow and the air above. The study's outcomes will provide insights into the processes linking atmospheric and subsurface phenomena on the wind erosion of coastal dunes. The findings can help identify vulnerable zones in coastal dunes, reduce hazards, and improve the resilience of coastal populations. Additionally, the results can lead to the development of erosion control techniques by analyzing the effects of vegetation and water content regulation mechanisms.This Research Infrastructure Improvement Track-4 EPSCoR Research Fellows (RII Track-4) project will provide a fellowship to an Assistant professor and training for a graduate student at the University of Maine. This work would be conducted in collaboration with researchers at the University of Florida. The project is based on the fundamental hypothesis that the mechanism of wind erosion in coastal dunes is significantly influenced by the competition between water evaporating from the dune to the wind flow and the repletion that occurs from the groundwater table to the surface by capillary rise, subsequently affecting its erodibility. This is a groundbreaking concept as it considers the role of groundwater elevation and capillary rise on the erodibility of coastal dunes for the first time. This hypothesis will be tested experimentally with a novel series of wind tunnel tests that will be carried out at the University of Florida's NSF Boundary Layer Wind Tunnel facility, part of the National Hazards Engineering Research Infrastructure facilities (NHERI). Furthermore, an analytical model based on solving mass conservation of water in the sand subsurface and the air above will provide the means to validate and extend the results of the wind tunnel experiments for large-scale and long-term conditions using the finite element method. The results of this study will provide insights into the processes linking atmospheric and subsurface phenomena to the wind erosion of coastal dunes.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.