The Landlab v1.0 OverlandFlow component: a Python tool for computing shallow-water flow across watersheds
The Landlab v1.0 OverlandFlow component: a Python tool for computing shallow-water flow across watersheds
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DOI：
10.5194/gmd-10-1645-2017
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发表时间：
2017-04-20
影响因子：
5.1
通讯作者：
Istanbulluoglu, Erkan
中科院分区：
文献类型：
--
作者：
Adams, Jordan M.;Gasparini, Nicole M.;Istanbulluoglu, Erkan
与水动力学模型相比，景观演化模型（LEMs）中流水的表示通常被简化，因为LEMs做出的假设减少了物理复杂性，有利于计算效率。Landlab建模框架可用于弥合复杂径流模型和更传统的LEM之间的鸿沟，创建一种在地貌学或水文学社区中不常用的新型框架。Landlab是一个Python语言库，其中包括可用于创建一系列时间和空间尺度上的地球表面动态模型的工具和流程组件。Landlab OverlandFlow组件基于浅水方程的简化惯性近似，遵循de Almeida等人（2012年）的解决方案。这种显式的二维水动力学算法模拟了洪水波在模型域，在结构化（栅格）网格内的所有位置计算排水量和流深。在这里，我们说明了如何包含在Landlab的OverlandFlow组件可以作为一个简化的基于事件的径流模型，以及如何耦合径流模型与切口模型在十年的时间尺度上运行。流路由的例子都真实的和合成景观。图中显示了美国科罗拉多斯普林克里克流域多个地点的单一风暴的水文图，沿着是流动的水作用于陆地表面的剪切应力图。OverlandFlow组件还可以与Landlab DetachmentLtdErosion组件耦合，以说明非稳定流路由方案如何影响流域上的切口。的过程线和切口的结果进行比较，模拟驱动的稳态径流。从耦合的径流和切口模型的结果表明，径流动力学可以影响景观的救济和渠道的绿化，这表明，在景观演变的时间尺度上，OverlandFlow模型可能会导致模拟的地形与传统方法相比的差异。中描述的探索性测试用例演示了如何在水文和地貌应用程序中使用OverlandFlow组件。
Representation of flowing water in landscape evolution models (LEMs) is often simplified compared to hydrodynamic models, as LEMs make assumptions reducing physical complexity in favor of computational efficiency. The Landlab modeling framework can be used to bridge the divide between complex runoff models and more traditional LEMs, creating a new type of framework not commonly used in the geomorphology or hydrology communities. Landlab is a Python-language library that includes tools and process components that can be used to create models of Earth-surface dynamics over a range of temporal and spatial scales. The Landlab OverlandFlow component is based on a simplified inertial approximation of the shallow water equations, following the solution of de Almeida et al. (2012). This explicit two-dimensional hydrodynamic algorithm simulates a flood wave across a model domain, where water discharge and flow depth are calculated at all locations within a structured (raster) grid. Here, we illustrate how the OverlandFlow component contained within Landlab can be applied as a simplified event-based runoff model and how to couple the runoff model with an incision model operating on decadal timescales. Examples of flow routing on both real and synthetic landscapes are shown. Hydrographs from a single storm at multiple locations in the Spring Creek watershed, Colorado, USA, are illustrated, along with a map of shear stress applied on the land surface by flowing water. The OverlandFlow component can also be coupled with the Landlab DetachmentLtdErosion component to illustrate how the non-steady flow routing regime impacts incision across a watershed. The hydrograph and incision results are compared to simulations driven by steady-state runoff. Results from the coupled runoff and incision model indicate that runoff dynamics can impact landscape relief and channel concavity, suggesting that, on landscape evolution timescales, the OverlandFlow model may lead to differences in simulated topography in comparison with traditional methods. The exploratory test cases described within demonstrate how the OverlandFlow component can be used in both hydrologic and geomorphic applications.