The relationship between the origin of tropical cyclones and their maximum attained intensity

Most tropical cyclones (TCs) originate from tropical disturbances over the western North Pacific (WNP). This study examines the tropical disturbances that developed into TCs and their relationship with maximum attained intensity. Using data from 1981 to 2020, we reveal that 29.1% of developing disturbances originated from Mixed Rossby–Gravity (MRG) waves. Compared with other origins, MRG-originated TCs intensify faster, produce more super typhoons, and reach higher lifetime maximum intensity (LMI). These developing systems typically form farther southeast and follow prolonged northwestward tracks, benefiting from a longer pre-LMI oceanic trajectory and greater exposure to favorable large-scale conditions, including warmer sea surface temperature, greater mid-level moisture, stronger convection and weaker vertical wind shear. Following their formation, the disturbances co-propagate westward with the MRG wave packet, which itself does not dissipate. 81.8% of these disturbances remain within the MRG wave packet until reaching their LMI, for an average duration of 3.7 days. The MRG wave packet provides favorable conditions for disturbance development, including warmer sea surface temperatures, enhanced moisture supply, reduced vertical wind shear, and stronger upper-level divergence—features that collectively promote intensification. Furthermore, the proportion of TCs statistically associated with MRG-related disturbances shows a significant increasing trend, underscoring an increasingly important role of MRG wave environments in modulating TC intensity.