Friday, 3 May 2002: 8:45 AM
The impact of oceanic heat content on hurricane intensity forecasts using the SHIPS model
Many studies have established a relationship between sea surface temperature (SST) and the formation and intensification of tropical cyclones. However, the oceanic response to tropical cyclones can reduce the SST by several degrees C, which can have a negative feedback on the storm intensity, especially for slow moving systems. The oceanic response to the storm is highly dependent on the sub-surface ocean structure. In regions where the oceanic mixed layer is deep, the SST cooling due to upwelling and mixing tends to be reduced, so there is considerably more thermal energy available to be transferred to the atmosphere. A method has been developed to estimate the heat content of the ocean using satellite altimetry data in combination with a two-layer ocean model. Ocean heat content analyses have been prepared for many tropical cyclone cases in the western Atlantic since 1993. In this study, the relationship between ocean heat content and tropical cyclone intensity change will be investigated for a large sample of cases. Tropical cyclone intensity change is also affected by the atmospheric environment (for example, by the vertical shear of the horizontal wind). Atmospheric factors will be accounted for by using the predictions from the Statistical Hurricane Intensity Prediction Scheme (SHIPS) as a baseline. The ocean heat content along the track of the storm will evaluated to determine if it helps to explain the differences between the SHIPS predicted and the observed intensity changes.
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