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Abstract Typhoon Hagibis (2019) explosively intensified by 100 kt in 24 h, greatly exceeding the conventional rapid intensification (RI) threshold of ∼30 kt per 24 h. This study investigates how marine heatwave (MHW)-driven ocean surface and subsurface structures influence such explosive RI (ERI). Using the coupled Weather Research and Forecasting and 3D Price–Weller–Pinkel Ocean model, we compared a Hagibis control run with two sensitivity experiments using non-MHW sea surface temperatures (SSTs) and vertical temperature profiles from another RI case of Typhoon Jebi (2018). Hagibis intensifies dramatically faster under MHW conditions—about 20% faster in the baseline simulation, and 40% faster when realistic vertical ocean mixing in the surface layer is included—revealing the striking sensitivity of ERI to upper-ocean thermal anomalies. Strong latent heat fluxes supplied continuous energy to the lower troposphere, while elevated subsurface heat content sustained air–sea enthalpy exchange despite storm-induced SST cooling. These ocean–atmosphere interactions reorganized TC convection, strengthened updrafts, and fostered an environment conducive to ERI. We conclude that even a 1 °C increase in surface temperature is sufficient to modulate storm structure and intensity, amplifying ERI. As ocean temperatures continue to rise, these findings highlight the need to refine the definition of ERI and improve our understanding of TC-ocean interactions under increasing MHW influence.
Choi et al. (Fri,) studied this question.