Increasing hurricane intensity in the Caribbean is linked to rising subsurface ocean temperatures

The devastation from Hurricanes Beryl and Melissa in 2024/5 highlights that tropical cyclones are frequent disasters in the Caribbean region. We find the average maximum sustained wind (MSW) has increased significantly by 30 kts since 1965 (5.3 kts per decade) and is significantly correlated with the rising subsurface ocean temperatures, which are increasing at 0.15°C per decade. In this study, the Tropical Cyclone Ocean-coupled Potential Intensity Model (TOPIM) was developed to improve estimates of potential intensity using subsurface ocean temperatures from ARGO floats and radiosonde data. We find that the average upper 100 m ocean temperature provides a closer estimate of the actual hurricane intensity than using sea surface temperature alone. The TOPIM model is also used in ocean sensitivity analysis. The results for historical Caribbean tropical cyclones suggest an average 25.7±3.4 kt increase in MSW for a 1°C increase in ocean temperature, and that Hurricanes Beryl and Melissa were 35 kts stronger associated with 1.5°C warmer than average ocean temperatures at the time of the hurricane. These results highlight the important role of rising ocean temperature to the increasing hurricane intensity being observed.