A Study of the Impact of Terrain on the Precipitation of “KROSA”
The impact of terrain on the precipitation during the landfall of “KROSA” (071 6) was analyzed with reanalysis data of JMA, topography data and the high resolu tion rain data generated by the variation method. The correlation coefficient be tween total precipitation and topography indicated that the terrain over Zhejian g largely affected the precipitation. The peak rainfall is located mainly on the windward hillsides. The distribution of frequency of different precipitation r anks showed that the relatively stronger precipitation happened in the topograp hic regions. The rain gains caused by the mountains along the southeastern coast of Zhejiang we re more than those caused by mountains along northeastern coast. With the reanal ysis data of JMA, the nondimensional number of flow crossing the topography was counted. As the value of Fr was small in this case, the air could flow over the hills more easily. The forced upward motion occurred windward in associati on with the heavy precipitation. The forced vertical velocity penetrated more de eply in southeastern coast than in northeastern coast, which might be the reason that the rain gains in southeastern coast were more than in northeastern coast.