Divergent trends in post-landfall decay of strong and weak tropical cyclones

Tropical cyclone post-landfall decay strongly influences inland hazard exposure, yet most studies assume that environmental change affects storms of different intensities uniformly. Here we identify an intensity-dependent divergence in global trends of tropical cyclone post-landfall decay. Analyzing 885 observed events (1979-2024), we show that strong storms (≥29 m/s) now weaken 18.6% faster after landfall, whereas weak storms persist 14.5% longer inland. These contrasting trends arise from different environmental sensitivities. Weak storms respond primarily to thermodynamic factors, including sea-surface warming, enhanced atmospheric moisture, and increased oceanic influence along storm tracks, all of which favor prolonged inland persistence. In contrast, strong storms are more sensitive to dynamic and land-surface conditions, including faster translation speeds, increasing atmospheric stability, and drier soil, which collectively promote faster decay. Numerical experiments further demonstrate that weaker storms respond more strongly to thermodynamic enhancement, whereas stronger storms are more vulnerable to dynamic disruption. These results challenge uniform-response assumptions in tropical cyclone risk assessment, forging a dual-threat landscape: intensifying coastal impacts from faster-decaying strong storms alongside expanding inland risks from increasingly persistent weak systems. Our findings reveal pronounced intensity-dependent heterogeneity in tropical cyclones, urging refined hazard assessment and adaptation for vulnerable and unprepared regions worldwide.