Comparative Study of Precipitation Characteristics and Causes of Similar Trajectories: Typhoons Chanthu and Mitag in the Western Pacific

Research on the differences and correlations of typhoon precipitation along similar trajectories, as well as their underlying causes, remains insufficient. Therefore, this study selects two typhoons with similar tracks but significantly different precipitation characteristics—Chanthu (2114) and Mitag (1918) in the Western Pacific—as research cases. Using the China Meteorological Administration best-track dataset, ERA5 reanalysis data, surface station observations, and GPM IMERG precipitation products, their precipitation features and underlying mechanisms are analyzed. Results show that the area-averaged land precipitation associated with Chanthu (51.9 mm) was nearly twice that of Mitag (27.2 mm). Chanthu produced broader and more persistent rainfall, mainly distributed along the northern side of its track, whereas Mitag exhibited weaker and more scattered precipitation. These differences were primarily related to the combined effects of large-scale circulation, moisture transport, dynamical and thermodynamic structure, and convective instability. During Chanthu, the subtropical high remained stable and the upper-level trough stayed farther north, favoring the maintenance of an organized typhoon structure. Chanthu also featured stronger upper-level divergence, sustained dual-channel moisture transport, a deeper warm-core structure, stronger upward motion, and better-developed convective instability. In contrast, Mitag was affected by the southward extension of the upper-level trough and the eastward retreat of the subtropical high, together with weaker divergence, insufficient moisture supply, a shallower structure, and weaker instability. Overall, precipitation differences between similarly tracked typhoons result from the synergistic effects of multiple environmental and internal factors. These findings improve understanding of typhoon precipitation mechanisms and may provide guidance for forecasting.