Hokkaido University, Sapporo, 060-0810, Japan.
Sci Rep. 2019 Jul 26;9(1):10866. doi: 10.1038/s41598-019-47291-5.
Persistent abnormal hot weather can cause considerable damage to human society and natural environments. In northern Eurasia, the recent change in summer surface air temperature exhibits a heterogeneous pattern with accelerated warming around the Eastern European Plain and Central Siberia, forming a wave train-like structure. However, the key factors that determine the magnitude and spatial distribution of this summer temperature trend remain unclear. Here, a huge ensemble of general circulation model (GCM) simulations show that the recent summer temperature trend has been intensified by two factors: steady warming induced by external forcing and inhomogeneous warming induced by internal atmosphere-land interactions that amplify quasi-stationary waves. The latter is sensitive to both snow cover and soil moisture anomalies in the spring, suggesting the potential of land surface monitoring for better seasonal prediction of summer temperatures. Dramatic changes in the circumpolar environment, characterised by Eurasian snow variation and Arctic Ocean warming, collectively affect summertime climate via memory effects of the land surface.
持续异常炎热的天气会对人类社会和自然环境造成相当大的破坏。在北欧亚大陆，最近夏季地表气温的变化呈现出一种不均匀的模式，东欧平原和西伯利亚中部的变暖速度加快，形成了波列状结构。然而，决定这一夏季温度趋势幅度和空间分布的关键因素尚不清楚。在这里，大量的通用环流模型（GCM）模拟显示，最近夏季温度趋势的增强是由两个因素造成的：外部强迫引起的稳定变暖，以及由内部大气-陆地相互作用引起的非均匀变暖，后者放大了准定常波。后者对春季积雪覆盖和土壤湿度异常敏感，这表明陆地表面监测有可能更好地预测夏季气温的季节性变化。环绕极区环境的剧烈变化，以欧亚大陆的雪量变化和北冰洋的变暖为特征，通过陆地表面的记忆效应共同影响夏季气候。
