Interdecadal variability of tropical cyclone intensification rates in the Western North Pacific

Abstract

Intensification rates of tropical cyclones (TCs) are critical in determining their lifetime maximum intensity and destructive power. However, the interdecadal variability of TC intensification rates in the Western North Pacific (WNP) remains unclear. In this study, we focused on the changes in TC intensification rates during 1980-2022 and found an abrupt increase in TC intensification rates after 2002. This change was primarily attributed to TCs undergoing rapid intensification (RI-TC). Furthermore, our investigations revealed that the RI-TC intensification rates were strongly related to the proportions of intensification rates ≥10 knots/6 h (IR-10) (r = 0.88), and the frequency of IR-10 events was highly correlated to sea surface temperature anomalies (r = 0.79), modulated by El Niño-Southern Oscillation and Interdecadal Pacific Oscillation. Additionally, we found that the IR-10 occurrence frequency shows a northwestward shift during 1980–2022, and this shift was primarily driven by 500 hPa vertical velocity, followed by vertical wind shear. These findings provide crucial insights into the evolution of TC intensification rates in the WNP over the past four decades. The role of IR-10 should not be underestimated in TC development, which could serve as a crucial parameter for the TC intensity prediction.