Diffusive Soil Transport and Hillslope Evolution

土壤扩散迁移和山坡演化

• 批准号: 0405119
• 负责人: David Furbish
• 金额: --
• 依托单位: Vanderbilt University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-08 至 2008-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0405119&HistoricalAwards=false
• 关键词: Diffusive; Soil; Transport; Hillslope; Evolution

PIs will pursue a comprehensive theory of diffusive soil transport and hillslope evolution associated with biological activity and surface rainsplash, building on recent, key developments in hillslope geomorphology. Their objectives are: (i) to clarify the fundamental ingredients and forms of constitutive (transport) laws describing these processes, demonstrating the conditions under which transport is proportional to the land-surface gradient or to the product of the soil thickness and surface gradient; (ii) to provide the analogue of a kinetic theory for the diffusion-like coefficient used in hillslope evolution models, demonstrating how it is an explicit nonlinear function of soil-particle activity, particle size, soil porosity and soil thickness, and indirectly related to climatic and biological conditions; (iii) to experimentally obtain the form of the constitutive law for transport by rainsplash using high-speed video and particle tracking techniques; (iv) to illustrate the fundamental significance of particle-activity gradients in producing transport, and demonstrate this using sandbox experiments for the case of rainsplash, and using field measurements of soil properties and tracer particles for the case of subsurface transport; (v) to clarify the ingredients of surface and subsurface particle dispersal, mixing and sorting, demonstrating how these processes contribute to hillslope catena structure; and (vi) to develop an advanced computational model of diffusive transport and hillslope evolution for exploring the full coupling between land-surface geometry, soil transport, soil thickness and soil production, including nonlinear responses to external and boundary forcing. This four-year program will mesh theoretical, experimental, field-based and computational components. The PIs theoretical work will focus on clarifying: (i) the ingredients of particle dispersal, mixing and sorting soil-depth and catena scale; and (ii) the forms of constitutive transport laws. PIs experimental/field work will: (i) focus on the process of rainsplash, and on particle mixing and sorting within soils, and at the soil surface; and (ii) be designed to test/validate the theoretical and computational aspects of their work. They will also apply high-performance algorithms based on discontinuous spectral element methods in developing advanced computational codes for simulating particle behavior at the soil-depth scale, and for simulating hillslope evolution at geomorphic scales. Under the auspices of the Center for Earth Surface Processes Center (CESPR), this project will involve collaboration of scientists expert in geomorphology, fluid mechanics, applied mathematics and advanced computations. The results of this work will constitute a major, and critical, contribution to the growing theoretical foundation of hillslope geomorphology.

PI将探讨与生物活性和表面雨水相关的扩散土壤运输和山坡演化的综合理论，这是基于山坡地貌的最新主要发展。 他们的目标是：（i）阐明描述这些过程的构成（运输）定律的基本成分和形式，以证明运输与土地表面梯度成正比的条件或土壤厚度和表面梯度的乘积； （ii）为山坡演化模型中使用的扩散系数提供了动力学理论的类似物，以证明它是土壤粒子活性的明确非线性功能，粒径，土壤孔隙率和土壤厚度以及与气候和生物条件间接相关的； （iii）使用高速视频和粒子跟踪技术实验地获得通过洗洗而进行运输的本构定律的形式； （iv）为了说明粒子活性梯度在产生运输中的基本意义，并使用沙盒实验对岩石扫描的情况进行了证明，并使用土壤特性和示踪剂颗粒的现场测量进行地下运输； （v）阐明表面和地下粒子分散，混合和排序的成分，证明了这些过程如何促进山坡catena结构； （vi）开发了一个高级计算模型的扩散运输和山坡演变，以探索土地表面几何形状，土壤传输，土壤厚度和土壤产量之间的完整耦合，包括对外部和边界强迫的非线性响应。 这个四年的计划将与理论，实验，基于现场和计算成分进行融合。 PIS理论工作将集中于澄清：（i）颗粒分散，混合和分类土壤深度和CATENA量表的成分； （ii）构成运输法的形式。 PIS实验/现场工作将：（i）专注于岩石的过程，以及土壤中和土壤表面的颗粒混合和分类； （ii）旨在测试/验证其工作的理论和计算方面。 他们还将在开发高级计算代码中基于不连续的光谱元素方法来应用高性能算法，以模拟土壤深度尺度上的粒子行为，并在地貌尺度上模拟山坡演化。 在地面过程中心（CESPR）的主持下，该项目将涉及科学家在地貌学，流体力学，应用数学和高级计算方面的合作。 这项工作的结果将构成对山坡地貌发展的不断发展的理论基础的重大且至关重要的贡献。