A theoretical model for rapid estimates of rainfall during tropical cyclones

A new, physical-based rainfall model for translating tropical cyclones was proposed in this study. This theoretical model was developed essentially based on the surface boundary condition where the total momentum flux (total surface stress) was decomposed into two contributions from wind and rain, respectively. An analytical wind field was utilized during the model construction leading to a linear analytical solution of the surface rain rate. The proposed rainfall model explicitly depends on parameters for a typical tropical cyclone wind field simulation, namely storm location, approach angle, translation speed, radius of maximum wind, pressure profile, surface drag coefficient, and turbulent diffusivity. Hence, it could be readily implemented into state-of-the-art tropical cyclone risk assessment using the Monte Carlo sampling methodology. Sensitivity analysis of the rainfall field to the abovementioned parameters was comprehensively conducted. The results generated by the present model are consistent with field measurements.