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

Perspective on the northwestward shift of autumn tropical cyclogenesis locations over the western North Pacific from shifting ENSO

“…3c, d, green bars), re-confirming that more and more TCs form over the northwestern WNP since 1998 (Fig. A3) from another angle, which is consistent with previous studies (e.g., Hsu et al 2014;Choi et al 2015Choi et al , 2017He et al 2015;Hong et al 2016;Zhao and Wang 2016;Huangfu et al 2017).…”

“…Over the WNP and the central North Pacific, the mean SST has significantly increased since 1998, together with a robust cooling over the central tropical Pacific (Fig. 4a, b), which is generally considered to be related to the late-1990s' Pacific decadal variability (e.g., Wang et al 2013, Hsu et al 2014He et al 2015;Hu et al 2016a;Hong et al 2014Hong et al , 2016Zhao and Wang 2016). Moreover, the patterns of ENSO-related decadal difference ( Fig.…”

“…Meanwhile, the western North Pacific (WNP) tropical cyclones (TCs) experience an active to less-active transition (see Fig. 1 of Hsu et al 2014 or He et al 2015). However, the percentage of TC intensification into typhoon during the late TC season (i.e., autumn) is higher than that in the peak TC season (i.e., summer) (Hsu et al 2014), especially in September (He et al 2017).…”

“…Although the interdecadal shift of WNP TCLs since the late-1990s has been widely studied (e.g., Chan 2013, Hsu et al 2014;Choi et al 2015Choi et al , 2017He et al 2015;Hong et al 2016;Zhao and Wang 2016;Huangfu et al 2017), these studies focused on the TC/typhoon activity associated with either ENSO phases or combined phases of PDO and ENSO (e.g., Zhao and Wang 2016). The combined effects of TUTT and MT modulated by shifting ENSO (i.e., two types of La Niña and two types of El Niño) on the concurrent WNP TCL change, however, have not been well investigated.…”

Regime shift of the South China Sea SST in the late 1990s

“…Understanding the characteristics and mechanisms responsible for this cold-to-warm SST regime shift is vital in view of its potential impacts on the climate variability over the Indo-Pacific basin. The present study is important while considering the decadal changes observed in the tropical cyclone activity over the SCS (He et al 2015), East Asian summer monsoon (Zhu et al 2011(Zhu et al , 2015Si and Ding 2013) and Indian summer monsoon (Yun et al 2010) in the late 1990s. The usage of multiple data products has limited our study from presenting a comprehensive discussion about the relative importance of air-sea heat fluxes and SCSTF/ PDO on the SST regime shift.…”