全球0.05°近地表冻融状态数据集v2.0（2002-2023）

近地表土壤的冻结/融化状态表征着陆地表层过程的休眠和活跃，这种冻融相态交替能引起一系列复杂的地表过程轨迹模式突变，影响着土壤的水热特性、地表径流和地下水补给等水循环过程，同时也通过水和能量循环机制影响气候变化。本数据集是基于AMSR-E、AMSR2被动微波亮温数据，结合MODIS地表温度和反照率光学遥感产品，利用冻融判别式算法和物理统计降尺度算法制备的全球近地表冻融状态（空间分辨率：0.05°；时间跨度：2002-2023年），经全球44个网络中1027个站点的土壤温度实测数据检验，总体判别精度达到了83.78%。本数据集可用于分析全球近地表冻融循环的开始/结束日期、冻结/融化时长、冻结范围等指标的空间分布和趋势变化，为理解全球变化背景下陆表冻融循环与水分、能量交换过程的相互作用机制提供数据支持。

Freeze/thaw state of near-surface soil characterizes the dormancy and activity of land surface processes. The alternation of freeze-thaw phases can trigger abrupt changes in the trajectory patterns of a series of complex land surface processes, affecting water cycle processes such as soil hydrothermal properties, surface runoff and groundwater recharge, and also influencing climate change through water and energy cycle mechanisms. This dataset is a global near-surface freeze/thaw product prepared based on AMSR-E and AMSR2 passive microwave brightness temperature data, combined with MODIS optical remote sensing products of land surface temperature and albedo, using freeze-thaw discriminant algorithms and physically based statistical downscaling algorithms. It has a spatial resolution of 0.05° and covers the period from 2002 to 2023. It was validated using in-situ soil temperature measurement data from 1027 sites across 44 global networks, with an overall classification accuracy of 83.78%. This dataset can be used to analyze the spatial distribution and temporal trends of indicators such as the start/end dates, freeze/thaw duration and freeze extent of global near-surface freeze-thaw cycles, providing data support for understanding the interaction mechanisms between land surface freeze-thaw cycles and water and energy exchange processes under the context of global change.