摘要:Abstract Tropical disturbances play an important role in the formation of tropical cyclones (TCs), but their climate characteristics are still poorly understood. The present study investigated the characteristics of tropical disturbances over the western North Pacific (WNP) for the period 1965–2020 using the reanalysis datasets. An algorithm based on the threshold of synoptic-scale vorticity and convection was developed to identify and track tropical disturbances. Approximately 116 tropical disturbances were detected primitively in the WNP from June to November each year, and about 13.1% of them subsequently developed into TCs. These developing disturbances contributed to the formation of 80.9% TCs in the WNP. Compared with nondeveloping disturbances, the position of developing disturbances is more eastward and southward, whereas the majority of their lifetimes and propagation speeds are similar. The annual numbers of developing disturbances exhibit significant interannual (interdecadal) variability. The percentage of TCs associated with disturbances also experiences a significant inverse interdecadal relationship with the number of TC genesis in the WNP, indicating that the formation probability of TCs is inconsistent with the transition probability from disturbances to TCs. In addition, the long-term trends of developing and nondeveloping disturbances suggest that global warming might be responsible for more tropical disturbances in the WNP instead of higher transition probability from disturbances to TCs.