Interdecadal variability of tropical cyclone genesis frequency in western North Pacific and South Pacific ocean basins

Abstract

Variability of tropical cyclone (TC) genesis frequency in the western North Pacific and South Pacific ocean basins in the interdecadal scale is studied. It is demonstrated that the TC genesis frequency in these ocean basins experienced an abrupt decrease near the end of the 20th century. The decreased occurrence of TC genesis in the two recent decades is mainly located in the low-latitude regions at the eastern side of the two ocean basins. It is also shown that a significant part of the decreased TC genesis occurred during October to December, i.e. the post-peak season in the western North Pacific ocean basin and the pre-peak season in the South Pacific ocean basin. The interdecadal trend of variation in the TC genesis frequency in these adjacent two ocean basins seems to be mainly due to a common mechanism, i.e. the variation in the atmospheric vorticity. In contrast to the decrease in the total TC genesis, the intense typhoon occurrence frequency experienced an interdecadal increase during the same period. This trend for intense typhoons is particularly clear in the western North Pacific ocean basin. The zonal distribution of the increased number in the intense typhoon occurrence shows a similar pattern to the increased value of the sea surface temperature. It is then suggested that the variation in the intense typhoon occurrence frequency in the western North Pacific ocean basin is related to a change in the La Niña-like sea surface warming pattern.

Variability of Tropical Cyclone Landfalls in China

“…S2 and S3, respectively, in the online supplemental material. Actually, the fact that the total number of TC events in the postpeak season experienced a significant decrease has been extensively studied (Hsu et al 2014;Shan and Yu 2020a). It may also be demonstrated that there are nearly no TC events belonging to the C2 type in the postpeak season.…”

“…In this study, we try to relate the variability of the TC landfalls in China or the variability of the TC occurrence frequency over the WNP ocean basin to the development of a La Niña-like sea surface warming pattern after the end of twentieth century (Liu and Chan 2013;Hsu et al 2014;Shan and Yu 2020a). In Fig.…”

“…A significant decrease in TC genesis frequency over the WNP at the end of the twentieth century has been reported in many recent studies (Liu and Chan 2013;Hu et al 2018). In addition, the abrupt decrease is identified to mainly occur in the postpeak season (October-December) rather than in the peak season (July-September) (Hsu et al 2014;Shan and Yu 2020a). The physical mechanism for this seasonal inhomogeneity of the abrupt decrease of TC genesis was clarified by Chang et al (2021), who claimed that significant anomalies of the equatorial easterly wind as well as the anticyclone occurred over the entire WNP and eventually induced an abrupt decrease of TC genesis in the postpeak season.…”

Distinct Interdecadal Change Contrasts Between Summer and Autumn in Latitude‐Longitude Covariability of Northwest Pacific Typhoon Genesis Locations

“…It is well known that the horizontal distribution of Pacific SST anomalies is the key factor for WNP typhoon activities (e.g., Choi et al., 2015; Guo & Tan, 2018; Hu et al., 2018; H. M. Kim et al., 2011; Shan & Yu, 2020; R. Wu et al., 2019; J. Zhao, Zhan, & Wang, 2018). Thus, we turn our attention to the potential impacts of Pacific SST change now.…”

Roles of interdecadal variability of the western North Pacific monsoon trough in shifting tropical cyclone formation

“…Although the MT activity linked with the PDO has little influence on the shift of the mean TC formation latitude, the number of TCs that form over the WNP experienced an interdecadal decrease during the end of the twentieth century (Yumoto and Matsuura 2001;Chan 2005;Huangfu et al 2017;Shan and Yu 2020). Not only the TC formation number, but the frequency of intense typhoon occurrence also exhibits decadal to multidecadal variations related to the PDO, since the favorable dynamic conditions (e.g., weak Fig.…”