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首页> 外文期刊>Catena: An Interdisciplinary Journal of Soil Science Hydrology-Geomorphology Focusing on Geoecology and Landscape Evolution >Flow-sediment relationship as functions of spatial and temporal scales in hilly areas of the Chinese Loess Plateau.
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Flow-sediment relationship as functions of spatial and temporal scales in hilly areas of the Chinese Loess Plateau.

机译：黄土高原丘陵区水沙关系与时空尺度的关系。

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摘要

Little information is available on the scale behavior of the flow-sediment relationship despite numerous studies on the scale behavior of sediment yield. Based on data observed at 19 gauging stations and 10 runoff experimental plots, we examined the flow-sediment relationship in the context of spatio-temporal scales for hilly loess areas, China. Distinct from many rivers around the world, sediment concentration in runoff is totally independent of flow discharge at any spatial scale for hilly loess areas. At the intra-event timescale, the relationship between flow discharge and sediment discharge can be well fitted by a proportional function especially at the entire slope (a combination of the hill slope and the channel side slope) and the larger scale. At the inter-event timescale, the variability of mean sediment concentration for a single runoff event decreases dramatically with increasing spatial scale. Accordingly, the proportional model of event runoff volume and sediment yield proposed in Zheng et al. (2007a and 2008) is applicable over a wide range of spatial scales from the hill slope to the large-sized watershed (up to 110, 000 km2). Both proportional models of the intra- and inter-event timescales are corroborated by the nonlinear regression technique, which yields a power fit with an exponent extremely close to 1. In a fully physical sense, however, the runoff-sediment yield relationship at the watershed scale should be linear with a negligible constant term due to the presence of base flow. At the annual timescale, the relationship between annual runoff volume and annual sediment yield at the watershed scale becomes linear with an indispensable constant term due to the higher proportion of base flow. The widely used power function is inappropriate for fitting the flow-sediment relationship in hilly loess areas at any spatio-temporal scales we examined. A comparable result was also obtained for the Walnut Gulch Experimental watershed of USA, suggesting that the proportional model may be universal for regions where sediment supply is sufficiently available.
机译：尽管对泥沙产量的尺度行为进行了大量研究，但关于流-泥沙关系的尺度行为的信息很少。基于在19个测量站和10个径流试验区的观测数据，我们研究了时空尺度下中国黄土丘陵区的水沙关系。与世界上许多河流不同，黄土丘陵区径流中的泥沙浓度完全独立于任何空间尺度的流量排放。在事件内时间尺度上，流量和沉积物排放之间的关系可以通过比例函数很好地拟合，特别是在整个坡度（山坡和河道边坡的组合）和更大的比例上。在事件间时间尺度上，单个径流事件的平均沉积物浓度变化随空间尺度的增加而显着降低。因此，Zheng等人提出了事件径流量与泥沙产量的比例模型。 （2007a和2008）适用于从山坡到大型集水区（最大110，000 km 2 ）的空间尺度。事件内和事件间时间比例的两个比例模型都通过非线性回归技术得到证实，该技术产生的幂拟合与指数非常接近1。但是，在完全物理意义上，分水岭处的径流-沉积物产量关系由于存在基流，标度应为线性且常数项可忽略不计。在年尺度上，由于基础流量的比例较高，因此在分水岭尺度上，年径流量与年产沙量之间的关系呈线性关系，具有不可或缺的常数项。在我们研究的任何时空尺度上，广泛使用的幂函数都不适合拟合丘陵黄土地区的流沙关系。美国的核桃谷实验流域也获得了可比的结果，表明比例模型对于沉积物供应充足的地区可能是通用的。

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