Effects of topography on TC tracks and precipitation distributions over land along the South China Coast

Numerical simulations have been performed using the Weather Research and Forecasting model to study how the presence of topography in southern China might contribute to the variations of tropical cyclone (TC) tracks and precipitation distributions over land. In examining the rainfall distributions with and without topography, larger rainfall enhancements in the right front (RF) quadrants are found in all simulated experiments with topography. TC tracks also found to be significantly different when comparing two situations. With topography, TCs move more westward at the beginning and have tendency to move to an area with higher and denser terrain near and after landfall in terms of track deviations. In another experiment that examines the differential contributions of local effect (coastal terrain) and remote effect (Taiwan terrain) on TC tracks and rainfall distributions over land, it is found that the local effect is dominant on the rainfall variations when the TCs made landfall in the western part of the South China Coast but its contribution becomes less and remote effect becomes significant for TCs making landfall along the eastern side of the coast. TC tracks in both situations also deviate from the experiments with presence of all topography. Hence TC tracks and precipitation distributions might be affected by topography and its differential effects can be divided into local and remote components.