The terrain elevation was derived from NASA׳s Shuttle Radar Topography Mission (SRTM 30) dataset version 2 (NASA, 2000). The original elevation data with the resolution of 90×90 m2 were converted into the UTM coordinate system, as shown in Fig. 2b. As the horizontal grid size of the model calculation is 3×3 km2, all terrain data were averaged to obtain the same spatial resolution as that of the model calculation.