CAJ | 학술논문

In this paper, the northward jump time of the western Pacifi c subtropical high (WPSH) is defi ned and analyzed on the interdecadal timescale. The results show that under global warming, signifi cant interdecadal changes have occurred in the time of the WPSH northward jumps. From 1951 to 2012, the time of the fi rst northward jump of WPSH has changed from“continuously early”to“continuously late”, with the transition occurring in 1980. The time of the second northward jump of WPSH shows a similar change, with the transition occurring in 1978. In this study, we off er a new perspective by using the time of the northward jump of WPSH to explain the eastern China summer rainfall pattern change from “north-abundant-south-below-average”to“south-abundant-north-below-average”at the end of the 1970s. The interdecadal change in the time of the northward jump of WPSH corresponds not only with the summer rainfall pattern, but also with the Pacifi c decadal oscillation (PDO). The WPSH northward jump time corresponding to the cold (warm) phase of the PDO is early (late). Although the PDO and the El Ni?no–Southern Oscillation (ENSO) both greatly infl uence the time of the two northward jumps of WPSH, the PDO’s eff ect is noticed before the ENSO’s by approximately 1–2 months. After excluding the ENSO infl uence, we derive composite vertical atmospheric circulation for diff erent phases of the PDO. The results show that during the cold (warm) phase of the PDO, the atmospheric circulations at 200, 500, and 850 hPa all contribute to an earlier (later) northward jump of the WPSH.