“麦莎”远距离台风暴雨的排熵指数分析

对2005年8月5日山东省一次远距离台风暴雨过程进行了诊断分析。从引起远距离台风暴雨的几个因素,分析此次山东地区强降水过程与台风“麦莎”及中纬度西风带系统的关系,判别台风暴雨的类型;应用耗散结构理论,分析了排熵指数与远距离台风暴雨区的关系。结果表明：该次暴雨过程是在远距离台风（0509号“麦莎”台风）和西风槽相互作用下产生的;非纬向的高、低空急流对本次暴雨过程起着重要作用;负熵变区（IRE〈0）对应着暴雨区,负熵变区的汇合反映远距离台风暴雨的落区,排熵指数对远距离台风暴雨分析预报有一定的指示作用。

Diagnostic Analysis of the Removal Entropy Index of the Far Distant Rainstorm of Typhoon Matsa

In this paper,the far distant rainstorm of Typhoon Matsa in Shandong Province on August 5, 2005 was analyzed. Based on several factors leading to the rainstorm far distant from the typhoon, relations were first analyzed between the strong rainstorm process and the westerly systems, and the rainstorm＇s type was judged. The concept of removal entropy index （IRE） was introduced on the basis of the theory of dissipative structure. Afterward the association of removal entropy index and the rainstorm in Shandong Province on August 5,2005 was analyzed. The results are as follows： the rainstorm was caused by the interaction between a westerly trough and the far distant typhoon （0509;Matsa） ;the non-zonal SE high-level jet and the SE low-level jet played an important role in this rainstorm process and the negative entropy change （IRE 〈 0） corresponded to the large-scale heavy rain, and the rain location of far distant rainstorm was consistent with the confluence of negative entropy change areas. The removal entropy index is able to provide very useful information for the forecasting of far distant typhoon rainstorm.