Understanding intraseasonal propagating oscillation in air temperature and its association with heatwaves over Eurasia during boreal summer

Eurasian heatwaves (HWs), which pose widespread and substantial risks on human livelihoods, have been reported to be related to intraseasonal atmospheric waves. Although previous studies have explored the quasi-stationary nature of these waves, the comprehension of their propagating properties and connection with summer HWs still remains elusive. Therefore, in this study, we aim to investigate the propagating oscillations in air temperature over Eurasia during boreal summer and establish its linkage with HWs. First, we examine eastward propagation signals using complex empirical orthogonal function (CEOF) method. According to the temperature budget analysis, it is found that the advection processes play a critical role in driving this eastward propagation, while the diabatic heating partly compensates. Subsequently, by employing a metric designed to quantify the intensity of propagation, a total of nine years which exhibits the strongest propagating signals are identified. A good association between the HWs and air temperature anomalies estimated by temperature advection can be observed, which indicates a robust linkage. Our results can reinforce the dynamical understanding of summer HWs over Eurasia, and it may also contribute to future monitoring and forecasting capabilities.