Numerical Studies of Tropical Cyclone Landfall Processes

Landfalling tropical cyclones (TCs, commonly known as typhoons in Asia) cause heavy rainfall, flooding, and landslips in addition to wind damage. Thus, being able to predict the changes in track as well as wind and rainfall distributions associated with a TC as it makes landfall is very important for any coastal community such as Hong Kong. However, our understanding of the underlying physical processes of such changes so far has been rather limited. At CityU, researchers have performed a number of studies in this area, the results of which have improved our understanding of the physical processes involved. This project represents a continuing effort of the CityU team to examine these issues further. Specifically, they propose to perform numerical simulations to identify (1) the relative roles of friction versus moisture fluxes, and (2) the contributions of vortex size and structure in producing the observed asymmetries in wind and rainfall distributions as well as track changes associated with TC landfall. The results of this study will enhance our understanding of the physical processes responsible for causing such changes, which will eventually translate to better predictions.