Key Laboratory of Remote Sensing of Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China.
Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Sci Total Environ. 2021 Jan 1;750:141670. doi: 10.1016/j.scitotenv.2020.141670. Epub 2020 Aug 15.
The timing and duration of snow cover critically affect surface albedo, surface energy budgets, and hydrological processes. Previous studies using in-situ or satellite remote sensing data have mostly been site-specific (Siberia and the Tibetan Plateau), and remote sensing and/or modeling data include large uncertainties. Here, we used 1103 stations with long-term (1966-2012) ground-based snow measurements to investigate spatial and temporal variability in snow cover timing and duration and factors impacting those changes across the Eurasian continent. We found the earliest annual onset and latest disappearance of snow cover occurred along the Arctic coast, where the long-term (1971-2000) mean annual snow cover duration (SCD) was more than nine months which was the longest in this study. The shortest SCD, ≤10 days, was found in southern China. The first and last dates of snow cover (FD and LD, respectively), SCD, and the ratio of SCD to snow season length (RDL) were generally latitude dependent over the Eurasian Continent, while were elevation dependent on the Tibetan Plateau. During the period from 1966 through 2012, FD delayed and LD advanced by ~1 day/decade, and RDL increased by about 0.01/decade. The LD, SCD, and RDL anomalies (relative to the period 1971-2000) were also significantly correlated with latitude. Advances in LD and positive RDL were more significant in low-latitude regions, decreases in SCD were more significant in high-latitude regions. Changes in SCD were related to air temperature and snowfall in autumn and warming in spring. SCD specifically increased in the northern Xinjiang and northeastern China due to increased snowfall. The significant reduction in SCD in southwestern Russia, the Tibetan Plateau and along the Yangtze River was mainly affected by climate warming.
积雪的时间和持续时间对地表反照率、地表能量收支和水文过程有至关重要的影响。以前使用现场或卫星遥感数据的研究大多是特定于地点的（西伯利亚和青藏高原），遥感和/或建模数据包含很大的不确定性。在这里，我们使用了 1103 个具有长期（1966-2012 年）地面积雪测量数据的站点，调查了欧亚大陆积雪开始和持续时间的空间和时间变化以及影响这些变化的因素。我们发现，北极海岸地区最早出现年度初雪和最晚出现积雪消融，那里的长期（1971-2000 年）平均年积雪持续时间（SCD）超过九个月，是本研究中最长的。在中国南部，SCD 最短，≤10 天。雪盖的最早和最晚日期（FD 和 LD）、SCD 和 SCD 与雪季长度的比值（RDL）在欧亚大陆上通常随纬度而变化，而在青藏高原上则随海拔而变化。在 1966 年至 2012 年期间，FD 推迟了约 1 天/十年，LD 提前了约 1 天/十年，RDL 增加了约 0.01/十年。LD、SCD 和 RDL 异常（相对于 1971-2000 年）也与纬度显著相关。低纬度地区 LD 提前和 RDL 正值增加更为显著，高纬度地区 SCD 减少更为显著。SCD 的变化与秋季的空气温度和降雪以及春季的变暖有关。由于降雪增加，北疆和东北地区的 SCD 明显增加。由于气候变暖，俄罗斯西南部、青藏高原和长江流域的 SCD 显著减少。
