ABSTRACT The East Asian Polar Front Jet (EAPJ) and the East Asian Subtropical Jet (EASJ) play pivotal roles in modulating regional climate. This study identifies a significant interdecadal shift in summer EAPJ–EASJ linkage during 1979–2024, with a distinct transition around 1994. During 1979–1994, the correlation between the two jets was weak and statistically insignificant ( r = −0.15). In contrast, the post–1995 period exhibited a strong negative correlation ( r = −0.69, p < 0.01), indicating a substantial intensification of the jet coupling. Further analysis suggests that the enhanced jet coupling was primarily driven by a phase shift of the Polar‐Eurasian (POL) pattern from negative to positive. This shift generated an equatorward‐propagating Rossby wave train that dynamically linked the two jets. Simultaneously, changes in the meridional potential vorticity gradient and upper‐level circulation pattern promoted enhanced equatorward‐propagating wave activity, thereby amplifying the jet coupling. Importantly, this interdecadal change in jet interaction has had substantial climatic consequences, particularly over the region of entire central‐northern‐northeastern Asia, where the intensified anticyclonic anomalies result in a notable increase in the frequency of extreme heat events.
Deng et al. (Mon,) studied this question.