Conservation equations governing hillslope responses: Exploring the physical basis of water balance
Conservation equations governing hillslope responses: Exploring the physical basis of water balance
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DOI：
10.1029/2000wr900066
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发表时间：
2000-07
影响因子：
5.4
通讯作者：
P. Reggiani;M. Sivapalan;S. Hassanizadeh
中科院分区：
文献类型：
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作者：
P. Reggiani;M. Sivapalan;S. Hassanizadeh
最近引入了一种用于推导流域尺度水文响应守恒方程的统一方法。该方法基于在称为代表性基本流域（REW）的平均区域上对相应的点尺度守恒方程进行时空平均。守恒方程的补充本构关系需要关闭的各种质量和动量交换条款。在本文中，我们总结了一个简单问题的结果方程，并展示了如何使用这些方程来模拟一个假设的REW的长期水平衡。该控制方程是根据非饱和区土壤的平均饱和度和流速以及饱和区土壤的平均厚度来制定的。该方程是耦合的常微分方程，是非线性的。他们的解决方案是同时进行的流域几何形状，土壤类型和大气强迫的各种组合。我们展示了如何相似性分析的控制方程可以导致一般的分类REWs有意义的无量纲相似性变量。此外，我们调查了长期的水平衡，并表明控制方程能够提供气候变化，土壤和地形控制对长期水平衡的影响的现实画面。
A unifying approach for the derivation of watershed‐scale conservation equations governing hydrologic responses has recently been introduced. The approach is based on space‐time averaging of the corresponding point‐scale conservation equations over an averaging region called the representative elementary watershed (REW). The conservation equations are supplemented by constitutive relationships needed for the closure of various mass and momentum exchange terms. In this paper, we present a summary of the resulting equations for a somewhat simpler problem and show how these equations can be employed to model the long‐term water balance of a single, hypothetical REW. The governing equations are formulated in terms of an average saturation and a flow velocity of the unsaturated zone soils and the average thickness of the saturated zone soils. The equations are coupled ordinary differential equations and are nonlinear. Their solution is carried out simultaneously for a variety of combinations of watershed geometry, soil type, and atmospheric forcing. We show how a similarity analysis of the governing equations can lead to a general classification of REWs in terms of meaningful dimensionless similarity variables. In addition, we investigate the long‐term water balance and show that the governing equations are able to provide a realistic picture of the impact of changing climate, soil, and topographic controls on long‐term water balance.