Observed Influences of Subpolar Front in the Japan/East Sea on Winter and Spring North Pacific Storm Track Activity

Abstract

This study investigated the response of the North Pacific storm track (NPST) activity to the meridional shift of the Japan/East Sea subpolar front during the cold season using a statistical method called generalized equilibrium feedback analysis. Results showed that the NPST response exhibits a basin‐wide anomaly in winter but a north‐south dipole in spring. Synoptic eddy temperature variance budget was employed to explore possible mechanisms from the perspective of eddy available potential energy (EAPE) generation. In winter, the baroclinic conversion directly induced by baroclinicity changes drives EAPE generation, and then, the positive eddy feedback reinforces this EAPE generation, giving rise to an intensified NPST. In spring, poleward‐shifted baroclinicity drives a displaced EAPE generation, leading to the poleward displacement of NPST. The shifted baroclinicity is caused by a basin‐scale warm air temperature anomaly, which is coherent with the anticyclone anomaly induced by the divergence of synoptic eddy heat and vorticity fluxes.