湖冰作为冰冻圈的重要组成部分，是反映全球气候变化最为直观的指示器之一。在气候变暖和人类活动加剧影响的背景下，全球湖泊冰情总体呈现冻结时间推迟、消融时间提前、冰期缩短、冰厚减薄等趋势特征。因此有必要对湖冰的时空变化特征进行精细化监测，为全球气候变化影响的规律分析和预警提供科学依据。由于现场勘测的局限性，遥感技术在湖冰监测中发挥了越来越重要的作用。已有大量研究利用不同的遥感传感器、从不同的湖冰参数与冰情物候特征对湖冰及其响应气候变化特征开展研究。本文结合国内外湖冰遥感监测现状，综述了湖冰监测常用的遥感数据源；再从湖冰范围识别方法、湖冰物候和冰厚参数遥感反演三个方面展开论述；并根据已有的相关文献报道，重点总结了当前湖冰研究热点区域及冰情变化趋势；最后，结合当前遥感技术的发展，探讨了未来多源遥感技术集成在湖冰监测中的应用潜力，以及对气候变化响应十分敏感的青藏高原地区湖冰研究的挑战。

Lake ice is not only an important part of the cryosphere but also one of the most direct indicators of global climate change. In the context of climate warming and intensified human activities, global lake ice presented a trend of delayed freeze onset date, advanced break onset date, shortened ice cover duration, and thinning ice thickness. This trend pretends to last for a long time. Consequently, a series of chain reactions of lake physical hydrology, hydrochemistry and ecosystem will inevitably be triggered, further heaving the burden of natural environment and habitat construction. Therefore, it is necessary to perform fine-scale monitoring and scientific analysis of spatiotemporal patterns on lake ice variations, further predicting the early warning of global climate change. Toward overcoming the limitation of in-situ surveys, remote sensing technique comes to play a significant role in lake ice monitoring, which can provide large-scale, long time series and high temporal resolution data for lake ice research. Currently, previous efforts always focus on lake ice and its response to climate change using different remote sensing sensors, parameters and characteristics. Through reviewing on the pioneering researches, this study presents a general review on the remote sensing data source and methods for lake ice studies, and spatial and temporal variations of lake ice in global hotspots. This paper first reviews the development of the commonly-used remote sensing data sources for lake ice monitoring, which includes spaceborne and airborne remote sensing platforms and existing lake-ice data products. Then, the methods of lake ice identification, and retrieval of lake ice phenology and ice thickness parameters are further compared and discussed. Threshold and index-based methods are commonly used in lake ice research. Further, according to the previous studies, this review summaries the research hotspots of lake ice and analyzes the spatial and temporal characteristics of lake ice variations. The research hotspots are mostly distributed in the Northern hemisphere, especially in Northern Europe, North America and the Tibetan Plateau. In addition, influencing factors of lake ice variations, including climate factors and lake shape attributes, are discussed in this study as well. Finally, the future development directions of lake ice study by remote sensing are discussed as follows: (1) to fully integrate multiple satellite data at medium and high spatial resolution to improve the accuracy of lake ice observation, particularly for small and medium-sized lakes; (2) to reconstruct the long time series of lake ice phenology and thickness information, and to predict their future changes based on the techniques such as the big earth data and machine learning methods; (3) to focus more on the research of past, present and future of lake ice variation characteristics in the Tibetan Plateau, which is rather sensitive to climate change and remains largely unexplained. Remote sensing is only an effective tool to monitor the variations of lake ice, yet what we should do imperatively is to advance the scientific understanding on climate change impacts and to take immediate actions.