EAR-PF: Resolving the multi-scale hydraulics of shallow overland flows on patchily-vegetated hillslopes: towards a simple predictive framework

Octavia V. Crompton博士被授予美国国家科学基金会地球科学博士后奖学金，以开发预测在强降雨事件期间从裸露土壤到植被地区的地表流量再分配的工具。这种再分配维持了年降雨量不足以支持植物生长的地区的生态系统。目前，这种水的再分配只能用复杂的、计算要求很高的数值模型来预测。克朗普顿博士的研究将把小尺度的水文过程与山坡的结果联系起来，以光秃秃和植被覆盖的地点的空间格局作为扩大规模的基础，从而简化这些预测。除了提供对旱地景观的陆地流物理的见解外，该研究还将为土地管理者和生态学家提供评估景观脆弱性和设计可行的恢复策略所需的基础科学知识。在她的博士后研究期间，她将受到杜克大学Gabriel Katul教授和意大利都灵工业大学Davide Poggi和Constantino Manes教授的指导。在杜克大学期间，克朗普顿博士将与杜克大学环境科学暑期项目合作，向来自STEM领域代表性不足群体的学生教授环境科学。为了扩大对定量环境科学的参与，克朗普顿博士将开发和教授一门关于环境过程计算建模的课程，以补充该项目现有的基于实地的学习方法。这项研究有几个目标：首先，一系列水槽实验将解决关于非常浅（3厘米深）的物理不确定性，渗透流过植被斑块。这将产生对这些流动的一些初步实验处理，并使人们对物理学有新的理解。其次，利用基于Saint-Venant方程的建模框架，将植被斑块的物理属性提升到斜坡尺度，并考虑空间异质性。最后，将开发从空间平均和流量分析近似中导出的简化复杂性模型，以预测山坡尺度的水文结果，并使用水槽实验对其预测进行测试。由此产生的工具将改进与旱地恢复、补救和保护有关的预测，使其能够明确描述风暴内水文过程的影响。该项目的更广泛影响将包括更好地了解旱地退化，旱地退化具有重大的社会和环境后果，影响到全球10%至20%的旱地，影响到约15亿人。本项目由地球科学部水文科学项目资助。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. Octavia V. Crompton has been awarded an NSF Earth Sciences Postdoctoral Fellowship to develop tools that predict the redistribution of surface flow from bare soil to vegetated areas during intense rainfall events. This redistribution maintains ecosystems in regions where annual rainfall alone is insufficient to support plant growth. At present, this water redistribution can only be predicted using complex and computationally demanding numerical models. Dr. Crompton’s research will simplify these predictions by linking hydrological processes on small scales to hillslope-outcomes using the spatial pattern of bare and vegetated sites as a basis for upscaling. In addition to providing insights into the physics of overland flow in dryland landscapes, the study will develop basic scientific knowledge needed by land managers and ecologists to assess landscape vulnerability and design viable restoration strategies. Dr. Crompton will be mentored during her postdoctoral research by Professor Gabriel Katul at Duke University, and Professors Davide Poggi and Constantino Manes at Turin Polytechnical University, Italy. While at Duke University, Dr. Crompton will partner with the Duke University Environmental Science Summer Program to teach environmental science to students from underrepresented groups in STEM. Aiming to broaden participation in quantitative environmental sciences, Dr. Crompton will develop and teach a curriculum on computational modeling of environmental processes, complementing the program's existing field-based learning approach. The research has several objectives: First, a series of flume experiments will resolve uncertainties regarding the physics of very shallow ( 3 cm deep), infiltrating flows through vegetation patches. This will generate some of the first experimental treatments of these flows, and enable new understanding of the physics. Second, a modeling framework based on the Saint-Venant equations will be used to upscale physics from vegetation patch to hillslope scales, accounting for spatial heterogeneity. Finally, reduced complexity models, derived from spatial averaging and analytical approximations to the flow, will be developed to predict hillslope-scale hydrological outcomes, and their predictions tested using flume experiments. The resulting tools will improve predictions relevant to dryland restoration, remediation and conservation, by enabling explicit description of the effects of within-storm hydrologic processes. Broader impacts of this project will include a better understanding of dryland degradation, which has large social and environmental consequences, affecting 10 to 20% of global drylands and impacting approximately 1.5 billion people. This project was funded by the Hydrological Science program in the Earth Science division.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.