In recent decades, unprecedented extreme summer heat waves have occurred in Europe, and they have exhibited an increasing trend since 1970s. Although previous studies have suggested that these recent hot European summers could have been instigated by the underlying surface thermal conditions, the possible influence of shrinking Arctic sea ice and Eurasian snow cover on heat waves are not well understood. Herein, we present evidence obtained via observational analyses and numerical experiments indicating that the interdecadal increase in European heat waves is closely linked to the reductions in Arctic sea ice concentration (ASIC) and Eurasian snow cover fraction (EASC) across mid–high latitudes via the excitation of the anomalous Eurasian wave train. The combined effects of declined ASIC and EASC, accompanied by the drier soil and the stronger heat flux, tend to weaken the poleward temperature gradient at mid–high latitudes and affect the midlatitude jet stream and transient eddy activities. These dynamic and thermodynamic circulations increase the likelihood of more persistent European blocking events that favor frequent and strengthened heat waves. Further projection analysis of simulations from 13 CMIP5 climate models suggests that Europe may experience more hot summers as the ASIC and EASC continue to decline over the next century.

近几十年来，欧洲发生了前所未有的极端夏季热浪，并且自1970年代以来，这种热浪呈上升趋势。尽管以前的研究表明，最近的欧洲夏季炎热可能是由于潜在的地表热条件引起的，但北极海冰和欧亚积雪萎缩对热浪的可能影响尚不清楚。在这里，我们提供通过观测分析和数值实验获得的证据，表明欧洲热浪的年代际增加与中高纬度的北极海冰浓度（ASIC）和欧亚积雪分数（EASC）的降低密切相关。激发异常的欧亚波列。ASIC和EASC下降的综合影响，伴随着较干燥的土壤和更强的热通量，往往会削弱中高纬度的极向温度梯度，并影响中纬度的急流和短暂的涡流活动。这些动态和热力学循环增加了欧洲发生更持久阻塞事件的可能性，这些事件有利于频繁和加强的热浪。对来自13个CMIP5气候模式的模拟进行的进一步预测分析表明，由于ASIC和EASC在下个世纪继续下降，欧洲可能会遇到更多炎热的夏天。