台风“碧利斯”的结构与江西暴雨诊断分析

DIAGNOSIS ANALYSIS OF STRUCTURE AND RAINSTORM OF THE TYPHOON "BILIS" IN JIANGXI

利用T213资料、自动气象站加密资料和常规观测资料等,研究分析了0604号台风“碧利斯”的环流背景、移动路径、内部结构和外围暴雨的分布特征,并将其与0505号台风“海棠”、0513号台风“泰利”、0414号台风“云娜”,进行了对比分析。研究结果表明,台风暴雨与台风环流场、热力场的不对称有关,并不一定总是集中在环流中心附近。无论是对称结构,还是非对称结构,降水中心都与强对流云带位置相对应。“碧利斯”先西北行后向西折的路径,主要是受强大稳定的副热带高压引导,并表现为明显的不对称结构,东侧、南侧的积云对流较为旺盛,降水主要集中在移动路径的第三象限;850hPa台风环流场表现为南部环流强盛,南海季风为西南急流的稳定维持提供了充沛的水汽条件;局地地形激发深厚的上升运动,进而产生庐山和赣南南部山区的大暴雨天气;垂直运动、散度、涡度、水汽通量、假相当位温等各物理量场,均与外围暴雨区有较好的对应关系。

Based on T213 analysis data,automatic meteorological station data and conventional observation data,we studied the circulation background,tracks,interior structure and distribution character of rainstorm of the typhoon BILIS,and made comparison with typhoon HAITANG,TELIM and RANANIM.The results show that typhoon rainstorm has relation to the dissymmetry of typhoon circulation fields and heat fields,but does not always close to the center of circulation.The center of rainstorm is always coincident with the location of severe convective cloud band in both symmetrical and dissymmetrical structure.BILIS moved first northwest then west guided by the stable subtropical high pressure.BILIS had clear dissymmetrical structure,the cumulus convection developed well in the south and east of it,and rainstorm mainly was in the third quadrant of BILIS' path.The south of the typhoon circulation fields of 850hPa develop well because the summer monsoon over South China Sea provided abundant moisture for the stability of south-westerly jet.Local terrain stimulated remarkable ascending movement that caused heavy rainstorm at Lushan and the south of Gannan.It was coincidence in space between the rainstorm area and physical variables,such as vertical speed,divergence,vorticity,water vapour flux and equivalent potential temperature.