Interdecadal variability of the early summer surface heat flux in the Kuroshio region and its impact on the Baiu frontal activity

In the Kuroshio region (KR), the early summer surface heat flux (SHF) exhibits a rapid increase around 1990 as a climate shift, which is rooted in the oceanic interdecadal variability in the North Pacific. The sea surface temperature (SST) in the KR, where SST is largely controlled by subsurface ocean circulations, is positively correlated with the local upward SHF. The positive SHF anomalies in the 1990s reinforced the Baiu frontal activity with an atmospheric large-scale meridional dipole in the western North Pacific. As such, the oceanic interdecadal variability has an impact on the atmospheric circulation through coherent SST and SHF variations even in early summer in the KR.