Decadal changes in tropical cyclone activity over the western North Pacific in the late 1990s

He Haozhe;Yang Jing;Gong Daoyi;Mao Rui;Wang Yuqing;Gao Miaoni

[He, Haozhe; Yang, Jing; Gong, Daoyi; Mao, Rui; Gao, Miaoni] Beijing Normal Univ, State Key Lab Earth Surface Proc & Resource Ecol, Beijing 100875, Peoples R China.

[Wang, Yuqing] Univ Hawaii Manoa, Int Pacific Res Ctr, Honolulu, HI 96825 USA.

[Wang, Yuqing] Univ Hawaii Manoa, Dept Atmospher Sci, Honolulu, HI 96825 USA.

ABSTRACT:  A pronounced decadal change in tropical cyclone (TC) activity over the western North Pacific (WNP) in the late 1990s was identified. Based on a comparison of the two epochs that occurred before and after the late 1990s, the TC genesis number exhibited an evident decrease over the southern WNP (S-WNP: 5A degrees-20A degrees N, 105A degrees-170A degrees E) and an increase over the northern WNP (N-WNP: 20A degrees-25A degrees N, 115A degrees-155A degrees E), which partly corresponded to a significant northward migration in the seasonal mean latitudinal location of TC genesis, i.e., from 17.2A degrees N to 18.7A degrees N. After the late 1990s, the northwestward-moving track became the most dominant track mode, accompanied by the weakening of both the westward-moving track and the northeastward-recurving track. Meanwhile, the TC occurrence frequency (TCF) experienced evident increases over southeastern China and the Okinawa islands, while prominent decreases occurred over the South China Sea, the Philippine Sea, Japan and east of Japan. Changes in the TCF were determined by TC genesis changes, TC track shifts and variations in regional TC durations, which were all ascribed to the decadal change in tropical Indo-Pacific sea surface temperature. The full picture on the decadal changes in the WNP TC activity revealed in this study may provide useful guidance for regional TC seasonal forecasts and future projections.

Published in CLIMATE DYNAMICS.2015,45(11-12):3317-3329, DOI: 10.1007/s00382-015-2541-1