闽南和台湾海峡地区次天气尺度强降水云团的研究

Research on medium-scale cloud clustes influencing both southern Fujian and Taiwan Strait

利用数字化卫星云图和高空探测资料，对比分析两个发生在不同天气背景下的次天气尺度强降水云团的发生，发展及对台湾地区天气的影响，得到一些有意义的结果。

By using digital cloud images of satellite and radlosnde data,two kinds of medium-scale cloud clusters, which occur in different meteorological situation (one in Mei-yu front and the other in low-level jet area )and broing about heavy rains to both side of Taiwan Strait,are investigated and compared. The character of the clustors' influence on Taiwan island is also discussed in this article. Some meaningful results have been gained as following.1．Two kinds of clusters are different in their source region. The jet-type cluster orignates in eastern Guangdoitg whereas the fronttype cluster comes from the northern part of Fujian. This difference results from the difference of trigger mechanism.2．Both clusters develope intensely in southern Fujian and eastern Guangdong. The cycloanic vorticity of middle and lower tropospheres are the main environmental forcing of front-type cloud cluster while the coupling of low-and high-level jet gives jet-type cluster a stronger upward condition The analyses also show that both clusters coincide with the maximum center of cyclon1c vorticlty at 500hPa.3．Jet-type cluster has a smaller horizontal scale than the front-type' s. Its center of intensity is situated in the west (cupwind) section of the cluster,whereas front-type cluster' s center coincide with its geometrical center. Both clusters show a oval-shape in mature stage.4. Both clusters have the same temporal variation of intensity,that is,developing after midnight,reaching maximum by sunset and becoming weak later on.5. Both clusters have a influence on Taiwan island. Generally speaking, it takes 3~ 6h from cluster's moving into the sea to having a influence on Taiwan island.