Predicting rapid intensity change of hurricanes

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Hurricanes, also named tropical cyclones in general, are the most violent and destructive weather phenomenon. Hurricanes have regularly resulted in annual economic losses exceeding $10 billions per year in the U.S. alone in the past decade. When a hurricane moves to higher latitudes, it can still pose a serious threat to land and maritime activities by producing intense rainfall, large waves, and strong winds. Accurate predictions of hurricanes are thus crucial to alleviate the costs. The track forecasts of hurricanes have been steadily improved over the last several decades. However, predicting their intensities, in particular the rapid intensity changes, remains a grand challenge. Better understanding of the mechanisms governing rapid intensity change (both intensification and weakening) in hurricanes is essential for improving the intensity forecast. We propose to study the dynamics and predictability of the hurricane rapid intensity change using observations, and numerical simulations of idealized and real hurricanes. The important questions that we want to answer are: a) What's the relative importance of hurricane inner-core structures to the rapid intensity change comparing to the large-scale environment? b) Can we use an ensemble 2D axisymmetric model with parameterized asymmetric structures to improve the forecast of the rapid intensity change? c) What's the predictability of the inner-core structures change and the resulting rapid intensity change? We will conduct idealized hurricane simulation using a model capable running in both 2D and 3D, and high-resolution ensemble data assimilation and forecast experiments for several hurricanes undergone rapid intensity changes. The simulations will be used to quantify the impacts of large-scale and storm-scale structures on the rapid intensity change. The proposed research will advance our understanding of hurricane rapid intensity change and improve the forecast.