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A new grid-free, hysteretic, and scale-dependent approach to modelling hillslope hydrology

一种新的无网格、滞后和尺度相关的山坡水文建模方法

基本信息

批准号：
NE/G017123/1
负责人：
Keith Beven
金额：
$ 29.72万
依托单位：
Lancaster University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG017123%2F1
关键词：
new grid free hysteretic scale

项目摘要

Classic 'physically-based' models of hillslope hydrology based on continuum mechanics have strong limitations when applied to the discrete water flow pathways that are often dominant in structured soils in the field. This project proposes a new modelling paradigm based on multiple interacting pathways, in which the water is represented as a very large number of discrete particles and exchanges between pathways are controlled by probabilistic rules. This allows flexibility in allowing for features of hillslope hydrology that are not easily handled within the continuum framework, such as the effect of vegetation on inputs rates at the soil surface, the effects of macropores and preferential flow pathways, and probabilistic representations of variable soil depths both across and down a slope. The particles representing the water can also be labelled by time of entry to the slope so that transport, mixing and residence time characteristics can be assessed within a single integrated framework (rather than requiring an additional dispersion equation in the continuum approach). The model has already been programmed for the simple case of a constant slope of unit width, but will be developed to allow for an arbitrary slope geometry and soil transmissivity characteristics. Mass balance is automatically achieved by accounting for all particles (including partial losses to evapotranspiration). There is also an intrinsic scaling of velocities and length scales so that the scaling characteristics of slopes can be investigated. This type of model is ideally suited to implementation on low-cost Graphics Processing Cards with high parallelism and this will be investigated to speed up the calculations. The model will be applied to data sets for flow and transport, for both steady state and transient flows, from the UK, Sweden, USA, Switzerland and Czech Republic, and there will be an opportunity to participate in planned tracer experiments in Czech Republic, China and the USA. Since much of the detail of flow pathways in field applications is inevitably unknowable, calibration of the model will be carried out within a multiple working hypothesis framework such that the multiple retained models will reflect the uncertainty arising from the characterisation of an application site.

基于连续介质力学的经典的基于物理的山坡水文学模型在应用于田间结构性土壤中通常占主导地位的离散水流路径时具有很强的局限性。该项目提出了一种基于多个相互作用的路径的新的建模范式，其中水被表示为非常大量的离散粒子，并且路径之间的交换由概率规则控制。这允许灵活地考虑在连续统框架内不容易处理的山坡水文特征，例如植被对土壤表面输入速率的影响、大孔隙和优先径流路径的影响以及坡面和坡下不同土壤深度的概率表示。代表水的颗粒还可以通过进入斜坡的时间来标记，以便可以在单一的综合框架内评估传输、混合和停留时间特性(而不需要在连续体法中附加的弥散方程)。该模型已经针对单位宽度的恒定坡度的简单情况编制了程序，但将发展为允许任意的坡度几何形状和土壤导水率特性。通过计算所有颗粒(包括蒸散的部分损失)，自动实现质量平衡。此外，还存在速度和长度尺度的内在标度，以便研究斜坡的标度特性。这种类型的模型非常适合在具有高并行性的低成本图形处理卡上实现，这将被研究以加速计算。该模型将应用于来自英国、瑞典、美国、瑞士和捷克共和国的流动和输运数据集，包括稳态和瞬变流动，并将有机会参与捷克共和国、中国和美国计划进行的示踪剂实验。由于现场应用中流动路径的许多细节不可避免地是未知的，因此模型的校准将在多工作假设框架内进行，以便多个保留的模型将反映由于应用现场的表征而产生的不确定性。