Negative Impact of Ocean on Tropical Cyclone Intensification

It is generally recognized that the intensity of tropical cyclones is strongly tied to the ocean sea surface temperature. While the vast majority of previous studies have emphasized the direct relationship of storm intensity with the warm water, far fewer have concentrated on the impact of cooler sea surface temperature anomalies that can often be found in the vicinity of a given storm system. Such cool anomalies can arise through TC-induced cold sea surface temperature wakes or as a result of the TC interaction with pre-existing cold-ocean eddies. Using a fully-coupled ocean/atmosphere mesoscale modeling system (COAMPS), we examine the impact of pre-existing and storm induced cool anomalies on the simulated intensity of several TCs from the Western Pacific, Gulf of Mexico, and Atlantic basins prior to making landfall. Both observations and the model forecasts indicate the storm at this time was generating a significant cold wake. The model shows a series of complex changes in the dynamics and thermodynamics of the TC and surrounding boundary layer that occur as the wake forms. A particular emphasis will be placed on the factors that influence the size and magnitude of the cold wake and its impact on the reduction in storm intensity as well as whether the cooling beneath the eyewall or further outside the eyewall have a greater contribution to the storm structure and intensity.