Abstract Knowledge of the spatiotemporal dynamics of the soil temperature in cold environments is key to understanding the effects of climate change on land–atmosphere feedback and ecosystem functions. Here, we quantify the recent thermal status and trends in shallow ground using the most up-to-date data set of over 457 sites in Russia. The data set consists of in situ soil temperatures at multiple depths (0.8, 1.6, and 3.2 m) collected from 1975 to 2016. For the region as a whole, significant soil warming occurred over the period. The mean annual soil temperature at depths of 0.8, 1.6, and 3.2 m increased at the same level, at ca 0.30–0.31 °C/decade, whereas the increase in maximum soil temperature ranged from 0.40 °C/decade at 0.8 m to 0.31 °C/decade at 3.2 m. Unlike the maximum soil temperature, the increases in minimum soil temperature did not vary (ca 0.25 °C/decade) with depth. Due to the overall greater increase in maximum soil temperature than minimum soil temperature, the intra-annual variability of soil temperature increased over the decades. Moreover, the soil temperature increased faster in the continuous permafrost area than in the discontinuous permafrost and seasonal frost areas at shallow depths (0.8 and 1.6 m depth), and increased slower at the deeper level (3.2 m). The warming rate of the maximum soil temperature at the shallower depths was less than that at the deeper level over the discontinuous permafrost area but greater over the seasonal frost area. However, the opposite was found regarding the increase in minimum soil temperature. Correlative analyses suggest that the trends in mean and extreme soil temperatures positively relate to the trends in snow cover thickness and duration, which results in the muted response of intra-annual variability of the soil temperature as snow cover changes. This study provides a comprehensive view of the decadal evolutions of the shallow soil temperatures over Russia, revealing that the temporal trends in annual mean and extreme soil temperatures vary with depth and permafrost distribution.

中文翻译：

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过去 40 年俄罗斯浅层土壤显着变暖

摘要 了解寒冷环境中土壤温度的时空动态是理解气候变化对陆-气反馈和生态系统功能影响的关键。在这里，我们使用俄罗斯超过 457 个站点的最新数据集量化了浅层最近的热状态和趋势。该数据集由 1975 年至 2016 年收集的多个深度（0.8、1.6 和 3.2 m）的原位土壤温度组成。对于整个地区而言，在此期间发生了显着的土壤变暖。0.8、1.6 和 3.2 m 深度的年平均土壤温度在同一水平上增加，约为 0.30–0.31 °C/decade，而最高土壤温度的增加范围为 0.40 °C/decade，在 0.8 m 到 0.31 °C/decade 在 3.2 m。与最高土壤温度不同，最低土壤温度的增加不随深度变化（约 0.25 °C/十年）。由于最高土壤温度的总体上升幅度大于最低土壤温度，因此土壤温度的年内变异性在过去几十年中有所增加。此外，在浅层（0.8 和1.6 m 深），连续多年冻土区的土壤温度比不连续多年冻土和季节性霜冻区的土壤温度升高更快，而在更深的水平（3.2 m）处升高较慢。在不连续多年冻土区，较浅层土壤最高温度的升温速率小于较深层，但在季节性霜冻区升温速率较大。然而，在最低土壤温度的增加方面发现了相反的情况。相关分析表明，平均和极端土壤温度的趋势与积雪厚度和持续时间的趋势正相关，这导致随着积雪变化的土壤温度年内变化的响应减弱。这项研究提供了俄罗斯浅层土壤温度十年演变的综合视图，揭示了年平均和极端土壤温度的时间趋势随深度和多年冻土分布而变化。