Tropical Cyclone Intensity and Structure: Improved Understanding and Prediction. Evaluation of Existing and Development of New Techniques for Global and Mesoscale NWP Model Assessment

This is the first year of a new grant. As such, I will briefly re-state the long-term goals. I am continuing research from my previous ONR grant on estimating the theoretical limits to tropical cyclone track errors, but with an emphasis now on distinguishing between overall track errors, and position and timing errors at landfall. My previous ONR grant showed a potential further halving of the mean absolute track errors over the major tropical cyclone (TC) basins. Because of the increased complexity, this error reduction is most likely to be even greater for TCs nearing or making landfall, so track error reduction will continue as a long-term goal. My second goal is to use both similar and new techniques to estimating the predictability limits of tropical cyclone intensity and intensity change out to at least 96 hours. Given that identified that there remain large errors in TC prediction, my third goal is to identify, quantify and reduce these sources of errors. My fourth goal is to improve the initial state specification for TCs by continuing the development and application of 4D data assimilation procedures, particularly with respect to the ingestion of newly emerging data sources. Model development also will continue throughout the period of the grant as such development is vital for improved predictions. I note here that for the third and fourth goals, special emphasis again will be placed on landfalling tropical cyclones, as they are the most destructive storms. My fifth, and final, goal is to address the crucial question of how best to assess NWP model forecast skill. The above goals all have significant implications for transitions.