Changes in Track and Structure of Tropical Cyclones near Landfall

Recent numerical studies have shown that differential friction between land and ocean can cause a tropical cyclone (TC) to drift towards land. In addition, differences in moisture together with those in roughness produce asymmetric convection, which tend to be offshore before the TC makes landfall but might shift towards the onshore side at or after landfall. In this paper, we will present results on how such a drift might be modified by the orientation or properties (non-uniform roughness) of the coastline Observational analyses of actual tracks will also be presented to verify the numerical results. Examinations of radar and satellite images of landfalling TCs along the South China coast also suggest that the numerical simulations are largely valid although in some cases, they cannot be verified because of the simplicity in the environmental flow in the simulations differ from those observed. Such convective distributions are also found to be related to the vertical wind shear.