Analysis of tropical cyclone intensification trends and variability in the North Atlantic Basin over the period 1970-2003

Over the past three decades, the sea-surface temperatures of the lower latitudes of the North Atlantic basin have increased while the lower-tropospheric temperatures show no upward trend. This differential warming of the atmosphere may have a destabilizing effect that could influence the development and intensification of tropical cyclones (TCs). In this investigation, we find that in general, TC intensification (a) is higher during the daytime period and during the later months of the storm season, (b) tends to be higher in the western portion of the North Atlantic basin, and (c) is not explained by current month or antecedent SSTs. Any changes associated with warming of the surface compared to a smaller temperature rise in the lower-troposphere (and resultant changes in atmospheric stability) have not produced detectable impacts on intensification rates of tropical cyclones in the North Atlantic basin.