雅鲁藏布江大拐弯地区河流地貌过程及负反馈响应机制研究

雅鲁藏布江（雅江）下游大拐弯地区汇聚了雅鲁藏布大峡谷及诸多下切支流，具有独特的地貌特征，其谷深坡陡，地壳运动活跃，峡谷地貌多处于脆弱临界平衡。在强降雨、地震等外营力扰动下，这一区域水文地质事件（山洪、崩塌、滑坡、泥石流等）频发，河流地貌在“稳定-失稳-稳定”之间动态调整，具有负反馈响应特征，研究其地貌过程和负反馈响应机制对于深入认识雅江的地貌演变有重要科学意义。项目聚焦雅江大拐弯地区峡谷段河床结构和河流地貌过程，基于系统的野外调查和定位观测，借助无人机航拍和遥感影像解译，探求峡谷地貌“平衡-失稳-平衡”的负反馈响应过程、机制和临界条件；阐明水文地质事件影响下河床结构的发育变化及河流地貌的动态响应。本研究的开展将有助于揭示雅江峡谷段地貌演变规律，明晰河床结构在地壳运动活跃区下切河流地貌稳定中的作用，为雅江大拐弯地区河流综合管理提供参考。

The great bend area of the lower reaches of the Yarlu Tsangpo River is a confluence of Yarlu Tsangpo Great Canyon and several incised tributaries. The canyon morphology is this area is very unique and generally in a critical equilibrium state, due to the deep incised valley, high gradient, and active tectonic motion. Under the disturbance of external forces (e.g., strong precipitation, earthquake), hydrogeologic events (such as torrential flood, avalanche, land slide, debris flow) occurs frequently in this area, inducing dynamic adjustment of fluvial morphology between states of “stable-unstable-restable”, and showing a characteristics of negative feedback. Investigation of the fluvial processes and the negative feedback mechanism is of scientific significance to understand morphology evolution of the Yarlu Tsangpo River. Based on systematical field investigation and position observation, and with the aid of unmanned aerial vehicle (UAV) photographing and remote sensing image analysis, the project will focus on streambed structure and fluvial processes in the great bend area to: (1) investigate the negative feedback processes, mechanism and critical conditions of valley morphology between states of “stable-unstable-restable” and (2) illustrate the development of streambed structure and dynamic response of fluvial pcocesses under the influence of hydrogeologic events. The study is conducive to reveal the evolution of canyon morphology of the Yarlu Tsanpo River, to clarify the effects of streambed structure on stability of fluvial morphology of incised rivers in tectonically active area, and to share reference for comprehensive management of rivers in the great bend area.