黄河青藏高原网状河段不同流量下活动河道的分布规律  

Distribution Rule of Active Channels Under Different Discharge of Anastomosing Reaches in the Tibetan Plateau of the Yellow River

作　　者：高超[1] 王随继 Gao Chao;Wang Suiji(Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室,北京100101 [2]中国科学院大学,北京100049

出　　处：《地理科学》2018年第4期618-627,共10页Scientia Geographica Sinica

基　　金：国家自然科学基金项目(41571005,41271027)资助~~

摘　　要：以黄河青藏高原阿万仓和采日玛两段主河道50 km与65 km长的网状河段为研究对象,利用2013年3期遥感影像绘制了不同流量下（176 m^3/s,978 m^3/s,1 610 m^3/s）网状河段活动河道的分布变化图,结合DEM数据分析了现有河道在流量增加过程中的空间分布格局和潜在定量关系。研究结果表明：根据流量大小划分出的3类活动河道,其分布规律基本是后者位于前者的两侧,据此可以推断,网状河分支河道基本是从主河道向两侧逐渐发展的。对于阿万仓河段,在河谷和河间地相对宽阔处,每个河道断面上3类活动河道数的比值为1∶1.67∶2.25;而在河谷较窄的地方,该比值为1∶1.22∶1.33。在采日玛河段,该比值分别为1∶1.3∶1.4和1∶0.95∶1.16。在宽阔的草原湿地河段,当网状河的主河道发生弯曲时,弯道内侧的活动河道数要大于弯道外侧的活动河道数。在平坦开阔的河谷地带,断面上的活动河道线密度与河谷宽度之间呈现出极好的线性负相关关系;而峡谷地带由于两侧高地形的限制,河谷宽窄不一,活动河道的线密度相对较大、且差别也较大。As an anastomosing river pattern located in the Qinghai-Tibetan Plateau, the Awancang and Cairima anastomosing channel reaches of the Yellow River were selected to be revealed the distribution features of the active channels in this study. The main channel length of the two anastomosing river reaches is 50 km and 65 km, respectively. Based on DEM data, three remote sensing images under different discharge conditions（176 m^3/s,978 m^3/s,1 610 m^3/s） in 2013, and established series of cross-sections with a interval about 2 km which perpendicular to the anastomosing channel belt, the active channels are classified into three kinds and the number of them and distance from active channel to the main channel on every cross-section were obtained. Furthermore, the spatial distribution characteristics of the active channels under the different discharge conditions were revealed. The results show that distribution rule of the three kinds of the active channels is the latter is on both sides of the former basically. From this we can infer that the branching channels in the anastomosing river reaches develop from the main channel to its both sides. For the Awancang anastomosing river reach, the ratio of the three kinds of the active channels on average of all cross-sections is 1∶1.67∶2.25 in the broader floodplain and grassland, while is 1∶1.22∶1.33 in the narrower valley section. For the Cairima anastomosing river reach, the ratio is 1∶1.3∶1.4 and 1∶0.95∶1.16, respectively. This phenomenon is beneficial to maintain the spatial balanced distribution and stability of the anastomosing channel system. In the reach of grassland without restrictions of valley, when the main channel occurs bends, the number of the active channels in the inner side of the curves is larger than that in the outside of the curves. In the reach of well-developed anastomosing morphology, there is an excellent linear negative correlation between the line density and valley width. While the line density of the active channels in valley

关 键 词：网状河流 活动河道 线密度 河谷宽度 黄河 

分 类 号：P931.1[天文地球—自然地理学]