气候变暖背景下，积雪正在发生显著的变化。第三极（青藏高原）和北极作为积雪在高海拔和高纬度地区的典型分布 区，备受科学界的关注。近60年来，第三极和北极的积雪范围和日数总体呈现减少趋势，但积雪深度的变化存在空间异质 性。积雪的变化与气候条件、大气环流和吸光性杂质的影响密不可分，同时，积雪变化对气候、水文、生态和人类系统也具 有重要反馈作用。对第三极和北极的积雪研究将为推动区域经济社会可持续发展提供重要基础数据和支撑。

There is a significant change of snow cover under global warming. More and more studies have focused on the variations in snow cover in the Third Pole (the Tibetan Plateau) and the Arctic because they are the typical distribution areas at high elevation (the Third Pole) and high latitude (the Arctic). Over the past 60 years, the trends of snow cover extent and duration have decreased significantly in the Third Pole and the Arctic, while there was a spatial inhomogeneity of change in snow depth. The change in snow cover is closely related to climatic conditions, atmospheric circulation, and the light-absorbing impurities. Snow cover also has an important feedback on climate, hydrological, ecological and human systems. The resolution of snow cover research would provide basic data and support for the regional economic and socially sustainable development.