In this paper, the northward jump time of the western Pacific subtropical high（WPSH） is defined and analyzed on the interdecadal timescale. The results show that under global warming, significant interdecadal change...In this paper, the northward jump time of the western Pacific subtropical high（WPSH） is defined and analyzed on the interdecadal timescale. The results show that under global warming, significant interdecadal changes have occurred in the time of the WPSH northward jumps. From 1951 to 2012, the time of the first 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 offer 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-southbelow-average＂ to ＂south-abundant-north-below-average＂ at the end of the 1970 s. The interdecadal change in the time of the northward jump of WPSH corresponds not only with the summer rainfall pattern, but also with the Pacific 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 Nino–Southern Oscillation（ENSO）both greatly influence the time of the two northward jumps of WPSH, the PDO＇s effect is noticed before the ENSO＇s by approximately 1–2 months. After excluding the ENSO influence, we derive composite vertical atmospheric circulation for different phases of the PDO. The results show that during the cold（warm）phase of the PDO, the atmospheric circulations at 200, 500, and 850 h Pa all contribute to an earlier（later）northward jump of the WPSH.展开更多
基金Supported by the National Basic Research and Development(973)Program of China(2013CB430204 and 2012CB955902)China Meteorological Administration Special Public Welfare Research Fund(GYHY201306021)National Natural Science Foundation of China(40930952,41105070,and 41375078)
文摘In this paper, the northward jump time of the western Pacific subtropical high（WPSH） is defined and analyzed on the interdecadal timescale. The results show that under global warming, significant interdecadal changes have occurred in the time of the WPSH northward jumps. From 1951 to 2012, the time of the first 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 offer 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-southbelow-average＂ to ＂south-abundant-north-below-average＂ at the end of the 1970 s. The interdecadal change in the time of the northward jump of WPSH corresponds not only with the summer rainfall pattern, but also with the Pacific 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 Nino–Southern Oscillation（ENSO）both greatly influence the time of the two northward jumps of WPSH, the PDO＇s effect is noticed before the ENSO＇s by approximately 1–2 months. After excluding the ENSO influence, we derive composite vertical atmospheric circulation for different phases of the PDO. The results show that during the cold（warm）phase of the PDO, the atmospheric circulations at 200, 500, and 850 h Pa all contribute to an earlier（later）northward jump of the WPSH.
