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

Abstract The intraseasonal oscillation of air temperature over Eurasia during boreal summer can cause extreme meteorological events such as heatwaves, which pose wide-spread and substantial risks on human livelihoods. Although the quasi-stationary nature of the Eurasian intraseasonal oscillations during boreal summer has been explored has been studied, its propagating properties and connection with heatwaves still remain elusive. Therefore, in this study, we aim to investigate the propagating oscillation in air temperature over Eurasia during boreal summer and 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 horizontal temperature advection plays 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 signal of air temperature intraseasonal oscillation, a total of 9 years with strong propagating signals are identified. A close association between the propagating HWs and reconstructed air temperature anomalies can be observed. Our results can reinforce the dynamical understanding of the summer air temperature intraseasonal propagating oscillation over Eurasia, and it may also contribute to future monitoring and forecasting capabilities.