QBO–TC Relationship in the Western North Pacific Is Nonstationary

Abstract The Quasi‐Biennial Oscillation (QBO) has been proposed as a key factor modulating tropical cyclone (TC) tracks in the western North Pacific, but its robustness remains controversial. This study revisits the QBO–TC relationship by extending the analysis period to 2024. The results reveal that the relationship is nonstationary and has changed sign around the 2000s. Before the 2000s, the westerly QBO phase was associated with an anticyclonic circulation anomaly over southeast Japan, favoring TC movement toward the East China Sea. After the 2000s, however, an anticyclonic circulation anomaly developed south of the East China Sea, hindering TC movement toward the region. This decadal change is likely influenced by internal climate variability rather than changes in the QBO itself or TC frequency. Consequently, the QBO may not serve as a robust predictor of western North Pacific TC tr…