南半球7619热带风暴的天气学分析

我国气象工作者对西南太平洋热带风暴的研究甚少,由于远洋活动的需要,有必要对这里的风暴形成规律做些研究,以利于预报服务工作的开展。7619号风暴是1976年4月25日在珊瑚海西北部热带辐合带(ITCZ)上生成的。它的全部生命史可分为酝酿、形成、发展和消亡四个阶段。各阶段有其清楚的天气学特征,在气压场、高度场、云图和温湿场(θ_se)的分布上,均可反映出来。本文着重分析了7619风暴的流场特征,点绘了各阶段中心附近纬向风速空间分布的经向剖面图。计算了该风暴形成前后,流入层平均纬向风速的水平切变值,其中心附近流场纬向风速的垂直切变值,得出了一些可供预报参考的结论。

THE SYNOPTIC METEOROLOGICAL ANALYSIS ON THE 7619 TROPICAL STORM IN THE SOUTHERN HEMISPHERE

According, to the analysis of the pressure field, the constant level chart,the temperature-humidity field (θ_se),the cloud chart and other materials, this paper discusses the development of Strom 7619 in detail. The emphasis is especially on the features of development in the streamline field. This paper states that the features of the horizontal shear and the vertical shear of the streamline field near the ITCZ are the most important factors for the generating and the dying of a storm. Storm 7619 formed in the deep Easterlies near the southern part of the ITCZ boundary in the area of the smallest vertical shear (2.0-5.0m/s),and in the ensuing 24-48 hours period the lower level shear value incresed rapidly. The above discussion will provide information for weather prediction.