Ongoing Poleward Migration of Tropical Cyclone Occurrence Over the Western North Pacific Ocean

Abstract

AbstractThe long‐term change of tropical cyclone (TC) occurrence (TCO) was investigated by combining TC track density function and empirical orthogonal function methods to consider TC duration through a new perspective. Pronounced ongoing poleward migration of TCO was found for 1982–2018. This change has primarily resulted from the modification of TC propagation from westward to northward since 1998. A cyclonic anomaly of the large‐scale environmental steering flow centered on East Asia was found based on a comparison of 1982–1997 and 1998–2018 periods. The cyclonic anomaly encompasses the southerly anomaly south of 20°N, which is the mainspring of the poleward migration of TCO, while the extra warming along the coast of China also favors this long‐term change. This study made it possible to analyze discrete spatiotemporal TC observations continuously and provided helpful techniques for projecting TC changes using numerical methods.