Topographic Influence of Taiwan Island on Typhoon "Matmo"

In this paper, the WRF model is used to study the topographic impact of the mountain range in central Taiwan Island on typhoon "Matmo" in 2014, including the typhoon intensity and distributions of winds and rain before and after "Matmo" made landfall in Taiwan Island. The results show that realistic representation of the topography could yield better simulations and reproduce the development process of Typhoon "Matmo". The Taiwan Island Central Mountain had a substantial impact on the moving path of "Matmo". In the experiment with a reduced height of topography in Taiwan Island, "Matmo" turned to the southwest compared to the observation; when increasing the topography height, "Matmo" turned to the northeast of its observed path. The degree of topography height change was positively correlated to the path deflection of "Matmo". Interaction between typhoon circulation and large-scale circulation was the main reason for the path deflection of "Matmo". Furthermore, changes in the topography height in Taiwan Island had obvious impacts on the typhoon intensity. Both increase and decrease in topography height in Taiwan Island would weaken the typhoon intensity, which was attributed to the dynamic narrow-tube effect and also related to cloud water distribution and convective activities. The mechanism for the topographic effect of Taiwan Island on typhoon precipitation was complicated. It was not only related to typhoon intensity and structure changes, but also associated with terrain-induced convective activities and spatio-temporal distribution of the spiral clouds in the peripheral region of typhoon.