Intra-event and inter-seasonal behaviour of suspended sediment in flash floods of the semi-arid northern Negev, Israel
Intra-event and inter-seasonal behaviour of suspended sediment in flash floods of the semi-arid northern Negev, Israel
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DOI：
10.1016/j.geomorph.2006.03.013
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发表时间：
2007-03
期刊：
影响因子：
3.9
通讯作者：
Y. Alexandrov;J. Laronne;I. Reid
中科院分区：
文献类型：
--
作者：
Y. Alexandrov;J. Laronne;I. Reid
认识到两种降雨事件的不同影响，其中包括漫游、离散、对流或对流增强的高强度风暴，可以更好地理解悬浮沉积物浓度与水量之间的关系；以及无处不在的、多单元的、低强度的锋面风暴。在黎凡特，第一种类型是秋季和春季的特征，高强度降雨的瞬时冲沙在悬沙-水排放关系中产生顺时针滞后。第二类为冬季特征，可表现为悬沙-水量关系逆时针或无滞回；沉积冲刷很少明显。由对流风暴引起的山洪中悬浮泥沙浓度很高（通常为104-105mg l - 1），但与水量的相关性很低（r=0.57）。相比之下，锋面暴雨径流携带的悬浮泥沙浓度较低（通常为103-104mg l−1），与水量的相关性较好（r=0.78）。这种划分有助于解释总体悬沙浓度-水量关系中明显的高度分散，但它揭示了关于细胞风暴路径配置和沉积物源区之间的相互作用还有很多有待了解的地方。
A better understanding of the relation between suspended sediment concentration and water discharge is gained by recognizing, amongst other things, the different impacts of two types of rainfall event: wandering, discrete, convective or convectively-enhanced, high intensity storms; and ubiquitous, multi-celled, low intensity, frontal storms. In the Levant, the first type is characteristic of autumn and spring and the flushing of sediment by the instant onset of high intensity rainfall produces a clockwise hysteresis in the suspended sediment–water discharge relation. The second type is characteristic of winter and can be marked by either anticlockwise or no hysteresis in the suspended sediment–water discharge relation; sedimentary flushing is rarely apparent. Suspended sediment concentrations in flash floods resulting from convective storms are high (typically 104–105mg l−1) but correlation with water discharge is low (r=0.57). In contrast, frontal storm runoff carries lower suspended sediment concentrations (typically 103–104mg l−1) and correlation with water discharge is better (r=0.78). This division assists in interpreting the high degree of scatter evident in the overall suspended sediment concentration–water discharge relation, but it reveals that much is yet to be learned about the interplay of the disposition of cellular storm tracks and sediment source areas.