Controls on Zero-Order Basin Morphology
Controls on Zero-Order Basin Morphology
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零级盆地形态的控制
DOI：
10.1029/2017jf004453
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Grieve S
中科院分区：
文献类型：
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作者：
Grieve S
零级流域是土壤覆盖景观的常见特征，定义为排水网络头部的无沟流域。它们的几何形状和体积控制着滑坡疏散后沉积物重新积聚的速度，更广泛地说，零级盆地控制着水和沉积物从山坡到河流网络的运动。它们还将水和沉积物输送到河流网络的最上部。尽管这一角色之间的缓和剂山坡和河流的过程中，很少有分析其形态进行了景观尺度。我们提出了一种方法来识别零阶盆地景观，随后量化其几何特性使用椭圆傅立叶分析。我们在美国考维塔水文实验室部署了这种方法。属性，如长度，浮雕，宽度和宽度遵循不同的概率分布，这可能会作为一个基础，用于测试未来的景观演变模型的预测。令人惊讶的是，在一个地形降水梯度和大山坡通道救济景观，我们观察海拔或空间位置和盆地几何形状之间没有相关性。然而，我们发现，两个自然地理单元在考埃塔有不同的零级盆地形态。这些是陡峭的、薄土的、高海拔的Nantahala陡崖和盆地的低坡度、低海拔、厚土的剩余部分。我们的研究结果表明，盆地坡度和面积负协变，产生不同的形式之间观察到的两个地文单位，我们建议通过空间变化的土壤蠕变和随机滑坡之间的竞争。
Zero‐order basins are common features of soil‐mantled landscapes, defined as unchanneled basins at the head of a drainage network. Their geometry and volume control how quickly sediment may reaccumulate after landslide evacuation and, more broadly, zero order basins govern the movement of water and sediment from hillslopes to the fluvial network. They also deliver water and sediment to the uppermost portions of the fluvial network. Despite this role as the moderator between hillslope and fluvial processes, little analysis on their morphology has been conducted at the landscape scale. We present a method to identify zero‐order basins in landscapes and subsequently quantify their geometric properties using elliptical Fourier analysis. We deploy this method across the Coweeta Hydrologic Laboratory, USA. Properties such as length, relief, width, and concavity follow distinct probability distributions, which may serve as a basis for testing predictions of future landscape evolution models. Surprisingly, in a landscape with an orographic precipitation gradient and large hillslope to channel relief, we observe no correlation between elevation or spatial location and basin geometry. However, we find that two physiographic units in Coweeta have distinct zero‐order basin morphologies. These are the steep, thin soiled, high‐elevation Nantahala Escarpment and the lower‐gradient, lower‐elevation, thick soiled remainder of the basin. Our results indicate that basin slope and area negatively covary, producing the distinct forms observed between the two physiographic units, which we suggest arise through competition between spatially variable soil creep and stochastic landsliding.