Hydrologic Connectivity and Patch‐To‐Hillslope Scale Relations in Dryland Ecosystems
Hydrologic Connectivity and Patch‐To‐Hillslope Scale Relations in Dryland Ecosystems
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DOI：
10.1029/2022gl101801
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发表时间：
2023-05
影响因子：
5.2
通讯作者：
O. Crompton;G. Katul;D. Lapides;S. Thompson
中科院分区：
文献类型：
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作者：
O. Crompton;G. Katul;D. Lapides;S. Thompson
在旱地，暴雨期间的径流将水分和养分从裸露的土壤区重新分配到植被区，为植被提供额外的资源。这种再分配的程度取决于表面粗糙度和渗透率之间的相互作用；植被斑块更大的渗透性促进了对植被的侵蚀，但更大的表面粗糙度会转移径流，形成绕过植被的曲折流动路径。在这里，使用2D圣维南方程在虚拟实验中检查这种相互作用，以测量径流连通性。利用流体平流的示踪剂来描绘流道。示踪剂源和汇点之间的距离在两个长度尺度上测量水文连通性：到山坡出口的连通性和坡内源-汇点的连通性。这些连通性长度尺度之间的差异表明了水流如何“绕过”山坡上的植被斑块。在山坡尺度上，径流系数和出水口连通性之间的幂律关系描述了山坡上的水分损失，为识别可能发生降水的景观提供了基础。
In drylands, runoff during storms redistributes water and nutrients from bare soil areas to vegetated patches, subsidizing vegetation with additional resources. The extent of this redistribution depends on the interplay between surface roughness and permeability; greater permeability in vegetated patches promotes run‐on to vegetation, but greater surface roughness diverts runoff, producing tortuous flow paths that bypass vegetation. Here, this interplay is examined in virtual experiments using the 2D Saint Venant Equations to measure runoff connectivity. Flowpaths are delineated using tracers advected by the flow. Distances between tracer sources and sinks along flowpaths measure hydrologic connectivity at two lengthscales: connectivity to the hillslope outlet and within‐slope source‐sink connectivity. Differences between these connectivity lengthscales indicate how flow may “by‐pass” vegetated patches within hillslopes. At the hillslope scale, a derived power‐law relation between the runoff coefficient and outlet connectivity describes hillslope water losses, providing a foundation for identifying landscapes likely to shed water.