Sea ice monitoring by polar orbiting satellites has been developed over more than four decades and is today one of the most well-established applications of space observations. This article gives an overview of data product development from the first sensors to the state-of-the-art regarding retrieval methods, new products and operational data sets serving climate monitoring as well as daily operational services including ice charting and forecasting. Passive microwave data has the longest history and represents the backbone of global ice monitoring with already more than four decades of consistent observations of ice concentration and extent. Time series of passive microwave data is the primary climate data set to document the sea ice decline in the Arctic. Scatterometer data is a valuable supplement to the passive microwave data, in particular to retrieve ice displacement and distinguish between firstyear and multiyear ice. Radar and laser altimeter data has become the main method to estimate sea ice thickness and thereby fill a gap in the observation of sea ice as an essential climate variable. Data on ice thickness allows estimation of ice volume and masses as well as improvement of the ice forecasts. The use of different altimetric frequencies also makes it possible to measure the depth of the snow covering the ice. Synthetic Aperture Radar (SAR) has become the work horse in operational ice observation on regional scale because high-resolution radar images are delivered year-round in nearly all regions where national ice services produce ice charts. Synthetic Aperture Radar data are also important for sea ice research because the data can be used to observe a number of sea ice processes and phenomena, like ice type development and sea ice dynamics, and thereby contribute to new knowledge about sea ice. The use of sea ice data products in modelling and forecasting services as well as in ice navigation is discussed. Finally, the article describes future plans for new satellites and sensors to be used in sea ice observation.

极地轨道卫星对海冰的监测已经发展了四十多年，如今已成为最完善的空间观测应用之一。本文概述了从第一个传感器到最先进的数据产品开发，涉及服务于气候监测的检索方法、新产品和业务数据集，以及包括冰图和预报在内的日常业务服务。被动微波数据具有最长的历史，代表了全球冰监测的支柱，对冰浓度和范围的一致观测已经超过 40 年。被动微波数据的时间序列是记录北极海冰减少的主要气候数据集。散射仪数据是对被动微波数据的宝贵补充，特别是检索冰位移并区分第一年和多年冰。雷达和激光高度计数据已成为估算海冰厚度的主要方法，填补了海冰作为重要气候变量观测的空白。关于冰厚度的数据可以估计冰的体积和质量以及改进冰的预报。使用不同的测高频率还可以测量覆盖冰层的积雪深度。合成孔径雷达 (SAR) 已成为区域范围内业务冰观测的主力军，因为高分辨率雷达图像几乎在国家冰服务机构制作冰图的所有地区全年提供。合成孔径雷达数据对于海冰研究也很重要，因为这些数据可用于观察许多海冰过程和现象，如冰类型发展和海冰动力学，从而有助于获得有关海冰的新知识。讨论了海冰数据产品在建模和预报服务以及冰区导航中的使用。最后，文章描述了用于海冰观测的新卫星和传感器的未来计划。