河流作为水循环系统的关键组成部分，对人类社会经济发展、流域的生态环境可持续性及区域气候的稳定都有着重要意义。因全球变暖、冰川冻土融化、洪旱灾害等对水文系统造成的干扰增强，河流的水文情势发生了深刻改变。随着传感器技术发展和卫星观测平台增加，（卫星）遥感技术手段逐渐成为当今监测河流水文的主流方法之一。各类遥感监测方式已广泛运用在河流面积/宽度提取和水位变化监测、径流量估算等方面研究，形成了全球或区域尺度的水文要素遥感产品。本文综述了基于光学影像、雷达影像、卫星测高等数据的河流水文要素遥感监测技术，分析和总结了利用遥感手段监测河流宽度与水域面积、水位、径流量等诸多要素及其变化的最新研究进展，并探讨前人研究的空间范围尺度和推广可行性。此外，青藏高原作为亚洲主要大江大河的发源地，同时也是水文站点监测资料极其缺乏的区域之一。利用遥感技术开展青藏高原河流水文监测的研究面临实测数据共享难、水文变化过程时空异质性极强、对暖湿化气候的响应特征复杂多变等难题。本文对各类水文遥感技术在青藏高原河流监测应用研究所取得的进展与存在的问题进行了回顾和展望，以期加深对该地区河流水文变化过程的理解。

Rivers are integral to the water cycle, underpinning human development, ecological health, and regional climate stability. Recently, global warming, glacial melt, and recurring hydrological disasters have intensified disturbances in river systems, necessitating broad-scale monitoring of complex hydrological changes. While traditional field measurements are valuable, limitations in their spatial and temporal coverage call for alternative approaches. With the advancement of sensor technology and the proliferation of satellite platforms, (satellite) remote sensing has emerged as a pivotal method for contemporary river hydrology monitoring. Compared to hydrological field measurements, it offers significant advantages in terms of real-time data acquisition, vast spatial coverage, and reduced economic costs. Various remote sensing monitoring techniques have been extensively applied to monitor river characteristics such as area/width, water level fluctuations, runoff estimation, and forming diverse-scale remote sensing products of hydrological elements. This paper reviews various monitoring techniques for river hydrological variables using optical or radar imaging and satellite altimetry. It analyzes the latest research progress in the hydrologic variables, encompassing river width, water area, water level, runoff, and their changes. Additionally, the spatial scale and feasibility of previous literature are thoroughly discussed. The Tibetan Plateau, known as the "Roof of the World", is one of the regions with a serious shortage of in-situ hydrological monitoring data, despite being the source of major rivers in Asia. The application of remote sensing technology for river hydrological monitoring on the Tibetan Plateau encounters challenges in data sharing, pronounced spatial and temporal heterogeneity of hydrological processes, and intricate response characteristics to a warming and humidification climate. This study begins by examining the main satellite remote sensing data sources and methods used to monitor various hydrological elements of rivers. It summarizes the current research progress in river hydrology monitoring using remote sensing technologies and explores future development opportunities. The review also addresses the advancements and challenges of hydrological remote sensing techniques specifically applied to river monitoring on the Tibetan Plateau. Several persistent issues in river hydrological remote sensing development have been identified: (1) The accuracy of extracting river area and width in regions with complex topography is severely affected by mixed pixels and spectral similarities. (2) In areas with sparse or no hydrological stations, assessing remote sensing data"s quality and potential applications remains challenging. (3) There is a notable lack of comprehensive monitoring and studies on the spatial and temporal patterns of hydrological changes in the inland flow areas of the Tibetan Plateau. Future research directions for remote sensing of river hydrology are outlined as follows: (1) Integrate multi-source remote sensing data and enhance the technologies and their applications for hydrological monitoring. (2) Optimize and innovate more universally applicable remote sensing algorithms for river hydrology. These priorities aim to address the critical challenges in hydrological remote sensing and enhance the capability and accuracy of monitoring systems, particularly in complex and underserved regions like the Tibetan Plateau. This paper aims to promote the deepening of river hydrology research on the Tibetan Plateau region, providing more accurate and scientific-technical support for practical water resources management and policy-making.