CAREER: Microtopography-Controlled Puddle-filling to Puddle-merging (P2P) Overland Flow Mechanism: Discontinuity, Variability, and Hierarchy

职业：微地形控制的水坑填充到水坑合并 (P2P) 地表水流机制：不连续性、变异性和层次结构

• 批准号: 0907588
• 负责人: Xuefeng Chu
• 金额: $ 37.85万
• 依托单位: North Dakota State University Fargo
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-11-03 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907588&HistoricalAwards=false
• 关键词: CAREER; Microtopography; Controlled; Puddle; filling

The objectives of the research are to: (1) develop improved, multi-scale methods to quantify the puddle-filling and puddle-merging (P2P) overland flow process under control of microtopography, with focus on characterizing discontinuity, variability, and hierarchy of overland flow; (2) develop a P2P overland flow modeling system that integrates the new methods and modeling techniques in a user-friendly Windows interface; and (3) improve hydrology education at all levels by providing an interactive, education-enhanced P2P teaching-learning software.Preliminary field data and previous studies highlight the important role of microtopography in overland flow generation and evolution, and emphasize the need for bridging the macro- and micro-scale hydrologic studies. Major challenges herein are: (1) effects of soil surface roughness on the P2P overland flow process are scale dependent; and (2) simply incorporating micro-scale effects of soil roughness in a larger-scale modeling framework can be computationally prohibitive. In this project, multi-scale methods, which involve dynamic puddle delineation and "point" and "area" modeling at two scale levels, will be developed to cope with these challenges and improve computational efficiency. Specifically, a quasi-three-dimensional model will be developed to simulate vertical infiltration into layered soils and rainfall excess at "points," and mass exchange and hydraulic connections between "points" over "areas" (puddle filling-connecting-merging process). The "point" modeling will be implemented on the cell/grid scale, while the "area" modeling will explicitly account for the effects of microrelief of cells on small-scale overland flow processes, such as flow types (microchannel flow or sheet flow) determined by an inundated factor. The P2P overland flow mechanism will also be examined by a series of laboratory and field experiments that reflect variability in soils, their spatial combination, roughness, and rainfall characteristics. Microrelief of the soil surfaces will be measured by using the laser scanner. The fractal model will be used to quantify soil surface roughness and scale effects of roughness will also be analyzed.A Windows-based P2P overland flow modeling system will be developed to enhance applications of the new methods. An interactive P2P teaching-learning software will be further developed for improving hydrology education at all levels. The educational software, with enhanced visualization capabilities, will integrate the new modeling techniques, computer-guided self-learning center, and a set of education-oriented tools and databases in a user-friendly Windows interface. The teaching-learning software will be used as the core for graduate and undergraduate hydrology courses, as well as other outreach programs.Intellectual Merit and Broader Impacts: The research on multi-scale P2P overland flow methods should be the first investigation of characterizing microtopography-controlled overland flow from a multi-scale perspective. The new methods will improve the understanding of intrinsic natures of overland flow: discontinuity, variability, and hierarchy. The models will be valuable tools for analyzing overland flow generation and evolution, and quantifying dynamic changes in the contributing areas of storm runoff, which is critical to nonpoint source pollution. Thus, this study will also have substantial impacts on environmental and ecological research and broad interdisciplinary application potentials. The user-friendly Windows P2P modeling system will particularly improve the accessibility to the new methods by the entire hydrology community. As an integral part of the NSF-funded LTER program, this unique hydrologic study will also provide valuable support for other LTER projects.The state-of-the-art, interactive software will be the first comprehensive teaching-learning tool specially designed for hydrology education at all levels. The software, with enhanced visualization capabilities, the computer-guided self-learning center, and hydrologic tools and databases, will not only effectively promote students' learning and interest in hydrologic sciences, but also benefit instructors by creating an active and innovative teaching-learning environment in their classes. Most importantly, the work will give the underrepresented students an excellent opportunity to conduct the cutting-edge hydrologic research and gain skills and experiences that are invaluable to their studies and future career.

研究的目标是：(1)发展改进的、多尺度的方法来量化微地形控制下的坡面流—水坑填充—水坑合并（P2P）过程，重点描述坡面流的不连续性、变异性和层次性；(2)开发一个P2P的陆地流建模系统，该系统在一个友好的Windows界面中集成了新的方法和建模技术；(3)通过提供互动式、教育增强型的P2P教学软件，提高各级水文教育水平。初步的野外资料和以往的研究都强调了微地形在坡面流产生和演化中的重要作用，强调了衔接宏观和微观水文研究的必要性。本文面临的主要挑战是：(1)土壤表面粗糙度对P2P坡面流过程的影响具有尺度依赖性；(2)简单地将土壤粗糙度的微尺度效应纳入更大规模的建模框架可能在计算上令人望而却步。在本项目中，将开发多尺度方法，包括动态水坑划定和两个尺度水平的“点”和“区域”建模，以应对这些挑战并提高计算效率。具体来说，将开发一个准三维模型来模拟分层土壤的垂直渗透和“点”上的降雨量过剩，以及“点”与“区域”之间的质量交换和水力连接（水坑填充-连接-合并过程）。“点”建模将在单元/网格尺度上实现，而“面积”建模将明确考虑单元微起伏对小尺度陆地流过程的影响，例如由淹没因子决定的流类型（微通道流或片流）。P2P的地表流机制也将通过一系列的实验室和现场实验来检验，这些实验反映了土壤的变异性、它们的空间组合、粗糙度和降雨特征。土壤表面的微起伏将用激光扫描仪测量。分形模型将用于量化土壤表面粗糙度，并分析粗糙度的尺度效应。将开发一个基于windows的P2P陆上流建模系统，以加强新方法的应用。进一步开发P2P互动式教学软件，提高各级水文学教育水平。该教育软件具有增强的可视化能力，将在用户友好的Windows界面中集成新的建模技术、计算机引导自学中心和一套面向教育的工具和数据库。该教学软件将作为研究生和本科生水文学课程以及其他推广项目的核心。知识价值和更广泛的影响：多尺度P2P坡面流方法的研究应该是第一个从多尺度角度研究微地形控制坡面流的研究。新方法将提高对地表流的内在性质的理解：不连续、变异性和层次性。这些模型将成为分析坡面流的产生和演变以及量化暴雨径流贡献区动态变化的有价值的工具，这对非点源污染至关重要。因此，本研究也将对环境与生态研究产生重大影响和广泛的跨学科应用潜力。用户友好的Windows P2P建模系统将特别提高整个水文界对新方法的可及性。作为美国国家科学基金会资助的LTER项目的组成部分，这项独特的水文研究也将为其他LTER项目提供宝贵的支持。最先进的交互式软件将是第一个专门为各级水文学教育设计的综合教学工具。该软件具有增强的可视化功能，计算机引导的自学中心，以及水文工具和数据库，不仅可以有效地促进学生对水文科学的学习和兴趣，而且还可以通过在课堂上创造活跃和创新的教与学环境使教师受益。最重要的是，这项工作将为未被充分代表的学生提供一个极好的机会，进行前沿的水文学研究，并获得对他们的学习和未来职业生涯非常宝贵的技能和经验。