Influence of Synoptic-Scale Waves on the Interdecadal Change in Tropical Cyclone Activity Over the Western North Pacific in the Early 2010s

In this study, we investigated the interdecadal change in tropical cyclone (TC) activity over the western North Pacific (WNP) in the early 2010s. At the western boundary of the WNP, the interdecadal change in TC activity exhibited a meridional tripole pattern. In contrast to the reduced activity over the northern South China Sea (SCS) and Taiwan, TC activity increased over the southern SCS and to the north of Shanghai after the early 2010s. Herein, we focused on the northern WNP. Over the last decade, frequent TC occurrences have affected East China, Korea and Japan. In this work, we examined the influence of synoptic-scale waves (SSWs) on the interdecadal change in TC activity. During the 2011-2021 period, SSWs tended to propagate northward, resulting in more TC tracks affecting the northern WNP and surrounding countries. In contrast, the westward-propagating SSWs before the early 2010s were more likely to favor westward-moving TCs.