River ice plays a crucial role in hydrology, ecosystems, and socio-economic systems in mid-to-high latitude regions. However, there is a notable gap in the analysis of patterns and trends in river ice phenologies and their influence factors at the river level. In this study, we developed a practical method to identify river ice phenologies by leveraging Landsat observations from 2000 to 2021, and established a comprehensive dataset encompassing 7970 river segments across the entire Northern Hemisphere. Our results revealed that the mean freeze-up date, break-up date, and ice duration for these river segments were October 24, May 4, and 192.1 days, respectively. Notably, 56% of the river segments exhibited a warming trend, with the average freeze-up date delayed by 2.7 days per decade, break-up date advanced by 2.5 days per decade, and ice duration shortened by 5.5 days per decade—nearly five times the documented decrease rate over the past 150 years. Furthermore, high-latitude polar regions and the Qinghai-Tibet Plateau demonstrated the most pronounced decreases in ice duration, exceeding 7.0 days per decade on average. We observed a substantial relative contribution, reaching up to 70%, of surface air temperature (SAT) in middle and low latitude regions characterized by relatively high winter temperatures. However, as winter temperatures decrease, the relative influence of SAT diminishes, while the contributions of precipitation, solar radiation, and residuals increase. Our dataset provided essential baseline for further understanding the fundamental physical processes within river systems, offering crucial insights for river management, hydrological disaster risk control, climate change research, and ecosystem conservation efforts.

中文翻译：

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2000-2021年北半球河流冰物候的格局和趋势


河冰在中高纬度地区的水文、生态系统和社会经济系统中发挥着至关重要的作用。然而，在河流层面的河流冰物候模式和趋势及其影响因素的分析方面存在显着差距。在这项研究中，我们利用 2000 年至 2021 年的 Landsat 观测数据开发了一种实用的方法来识别河流冰物候，并建立了涵盖整个北半球 7970 个河流段的综合数据集。我们的结果显示，这些河段的平均结冰日期、崩解日期和结冰持续时间分别为 10 月 24 日、5 月 4 日和 192.1 天。值得注意的是，56%的河段呈现变暖趋势，平均封冻期每10年推迟2.7天，解冻期每10年提前2.5天，结冰期每10年缩短5.5天，接近5天。过去 150 年有记载的下降率的倍数。此外，高纬度极地地区和青藏高原的冰期减少最为明显，平均每十年超过7.0天。我们观察到，在冬季气温相对较高的中低纬度地区，地表气温 (SAT) 的相对贡献相当大，高达 70%。然而，随着冬季气温降低，SAT 的相对影响减弱，而降水、太阳辐射和残差的贡献则增加。我们的数据集为进一步了解河流系统内的基本物理过程提供了必要的基线，为河流管理、水文灾害风险控制、气候变化研究和生态系统保护工作提供了重要的见解。