The high latitudes are a hotspot for past and future climate change as forced climate signals have begun to emerge from internal variability in recent decades. New tools, such as initial condition large ensembles, provide a simulated range of possible climate realities that allow for separating the externally forced and internally variable components of the climate system. In addition, interactions between environmental variables and atmospheric circulation patterns can be detected in an unforced climate scenario and removed to isolate thermodynamic influences on the climate system. In the Arctic, this separation between dynamic and thermodynamic influences can be used to examine the impact of permafrost degradation on surface air temperatures (SAT). While impacts from permafrost degradation and subsequent carbon release have been thoroughly studied, geophysical influences have not received as much attention. This study employs the Community Earth System Model’s Large Ensemble to simulate and analyze these geophysical impacts over three time periods: 1976–2005, 2021–2050, and 2071–2100. As soil is thawing earlier and freezing later, we focus on spring and autumn to determine permafrost’s thermodynamic influence on SAT across Eurasia. We find that large internal variability, primarily due to atmospheric dynamics, affects spring SATs through 2100 while variability in autumn SATs will decrease over time due to increasing thermodynamic surface factors. These thermodynamic surface influences are most prominent in areas of continuous and discontinuous permafrost and lesser in non-permafrost regions, likely the result of a changing seasonal surface energy budget resulting from degradation and loss of permafrost.

高纬度地区是过去和未来气候变化的热点，因为近几十年来内部气候的变化已开始产生强迫性气候信号。新工具（例如初始条件的大型合奏）提供了可能的气候现实条件的模拟范围，从而可以将气候系统的外部和内部可变部分分开。此外，可以在非强迫性气候情况下检测环境变量与大气环流模式之间的相互作用，并将其删除以隔离对气候系统的热力学影响。在北极，动态影响和热力学影响之间的这种隔离可用于检查永久冻土退化对地表气温（SAT）的影响。尽管已经对永冻土退化和随后的碳释放的影响进行了深入研究，但地球物理影响并未引起人们的广泛关注。这项研究采用了“社区地球系统模型”的大集合来模拟和分析三个时间段（1976–2005、2021–2050和2071–2100）中的这些地球物理影响。由于土壤融化较早，随后融化，我们将重点放在春季和秋季，以确定多年冻土对欧亚大陆上SAT的热力学影响。我们发现，主要由于大气动力学的较大内部变化会影响到2100年春季的SAT，而秋季SAT的变化会由于热力学表面因子的增加而随着时间的推移而降低。这些热力学表面影响在连续和不连续的多年冻土地区最为突出，而在非多年冻土地区则较少，