青藏高原积雪范围和雪深/雪水当量遥感反演研究进展及挑战

积雪是地表特征的重要参数，对辐射收支、气候和长期天气变化均有重要影响。雪本身又是一个重要的天气现象和水文气象参数，过量的降雪也会带来严重的雪灾，如牧区雪灾、雪崩和融雪洪水灾害等。因此对积雪的监测，尤其是对山区的积雪监测，具有多方面的意义。利用卫星遥感技术监测积雪已有50余年的历史，并已形成了系列业务产品。青藏高原平均海拔超过4 000 m，该地区的积雪具有重要的水文、气候和生态环境意义。由于地形复杂，人迹罕至，地面观测站点稀少，受较强太阳辐射的影响，积雪消融迅速、区域差异消融以及风吹雪等因素导致积雪分布破碎化严重，对使用遥感资料监测该地区的积雪造成的极大的困难和不确定性。随着国内外传感器技术的不断发展，光学和被动微波遥感数据的同步获取技术已经非常成熟，综合利用光学遥感数据高空间分辨率和被动微波数据不受云干扰的特点，结合机器学习、无人机等技术，将环境参数加入反演模型中，有助于提高青藏高原积雪参数反演精度。

Remote sensing inversion of snow cover extent and snow depth/snow water equivalent on the Qinghai-Tibet Plateau: advance and challenge

Snow cover is an important parameter of surface characteristics, which has an important impact on radiation budget, climate and long-term weather changes. Snow itself is an important weather phenomenon, and is an important hydrometeorological parameter, but also brings disastrous weather and hydrological disasters, such as pastoral snow disaster, avalanches and snowmelt floods. Therefore, the monitoring of snow, especially the monitoring of snow in mountain areas, is of great significance in many aspects. The use of satellite remote sensing technology to monitor snow cover has a history of more than 30 years, and has formed operational products. With the development of remote sensing technology, the corresponding monitoring methods are also in the process of continuous development and progress. The snow cover in Qinghai-Tibet Plateau is of great hydrological, climatic and ecological significance. Therefore, the research on snow parameters extraction of the specific area on the Qinghai-Tibet Plateau by using remote sensing technology, not only can effectively improve snow monitoring accuracy, in order to evaluate the snow cover change accurately, but also can provide more accurate input snow factors for hydrology and climate models, and enhance the contribution of snow research of China in the world. The Qinghai-Tibet Plateau has an average altitude above 4 000 m. The ground observation stations are rare in this plateau. Affected by strong solar radiation and complex terrain, the rapid melting of snow, regional difference ablation and wind blowing snow and other factors lead to the serious fragmentation of snow cover distribution, which makes it difficult and uncertain to use remote sensing data to monitor the snow cover in this area. With the progress of satellite and sensor technologies, especially a series of FY satellite launch and run successfully in China, the synchronization observe technology by optical and passive microwave remote sensing is already mature. Effectively use the advantage of higher spatial resolution of optical remote sensing data and cloud penetration of passive microwave remote sensing data, combined with machine learning, UAV and other technologies, will be an effective way to improve the accuracy of snow parameters inversion in Qinghai-Tibet Plateau.