Prominent influence of salinity on Atlantic hurricane rapid intensification

Rapid Intensification (RI) of hurricanes is difficult to predict and poses a formidable threat to coastal populations. While a warm upper-ocean is well-known to favor RI, the role of salinity is less clear. In this study, using a suite of observations, we demonstrate that the subsurface oceans' influence on Atlantic hurricane RI exhibits two regimes. In the western region, which includes the Gulf of Mexico and the western Caribbean Sea, temperature stratification plays an important role in hurricane RI with little impact from salinity. On the other hand, in the eastern region dominated by the Amazon-Orinoco plume, salinity stratification prominently impacts RI. While a weak temperature stratification aids cold wake reduction for hurricanes in the western region, a strong salinity stratification causes less hurricane-induced mixing and surface cooling in the eastern region. Finally, in both regions, the relevance of the cold wake, and consequently the ocean sub-surface, is enhanced during RI compared to weaker intensification.