Dry soil moisture on the Tibetan plateau drives synchronous extreme heatwaves in Europe and East Asia

Recently, extreme heatwaves have frequently concurrently swept across Europe and East Asia, causing severe cascading socioeconomic consequences. However, the nonlinear synchronization relationship between these heatwaves and their underlying physical mechanisms remains poorly understood. Utilizing the event synchronization climate network method, atmospheric dynamic diagnostics, and numerical experiments, we revealed robust synchronization between heatwaves over Europe and East Asia, strongly associated with dry soil moisture conditions over the Tibetan Plateau from the preceding winter to summer. Dry soil moisture triggers an equivalent barotropic anticyclone north of the Tibetan Plateau, coinciding with the subtropical westerly jet waveguide and initiating circumglobal atmospheric Rossby waves propagating westward and eastward. Consequently, an equivalent barotropic anticyclone develops over Europe. These anticyclones induce simultaneous heatwaves across Europe and East Asia by increasing downward solar radiation and adiabatic sinking, amplified by positive land-atmosphere feedback. Our findings significantly enhance the understanding and predictive capabilities of these synchronous heatwaves across Eurasia.