对“9.3”昌化特大暴雨过程的成因分析  

An analysis of the reasons for "9.3" abrupt heavy reainstorm in Changhua

作　　者：陈丽芳[1] 

机构地区：[1]杭州市气象局,浙江杭州310008

出　　处：《浙江大学学报（理学版）》2008年第3期348-354,共7页Journal of Zhejiang University（Science Edition）

基　　金：浙江省气象科技计划项目资助(2006qn010)

摘　　要：2005年9月3、4日在浙江昌化地区发生的特大暴雨是历史上罕见的特大暴雨,雨强极大,且位于大范围的暴雨区之外.对此次特大暴雨成因进行分析,得到一些结论:"昌化暴雨"的影响系统较为复杂,由"泰利"台风、"彩蝶"台风外围低空急流、西太平洋副热带高压边缘上升气流、西风槽这些系统相互作用而形成.特殊地形的热力和动力强迫作用有利于α-小尺度垂直次级环流的形成.东低西高的盆地地形有利于在盆地内形成一个东侧下沉,西侧上升的α-小尺度垂直次级环流.天目山脉阻挡了冷空气,但边界层内弱冷空气却沿河谷侵入盆地,形成盆地周围小尺度的能量锋区,从而激发出远离暴雨区的孤立的强对流天气.台风"彩蝶"第2象限的东风和副高底部的东风叠加形成的东风急流是本次暴雨重要的水汽来源.昌化地区近地面存在风向风速的辐合,并且长时间维持,造成雨团的停滞.高层高位涡区与暴雨环流的高位涡区上下连通,使得高层的高位涡向低层补充,引起低层正涡度发展,为超强降水的形成提供了动力条件.暴雨发生在高湿高能的环境下,是不稳定的强对流降水,与"泰利"低压的层结稳定降水性质不同.Systematical analyses were carried out for an abrupt heavy rainstorm in Changhua of Zheiiang Province on September 3, 2005. The results show that because of the easterlies and westerlies confronting each other, the circulation was stabilization. Saddle-circulation was the background of this storm. Dynamic and thermal function by the special relief were use of the forming of perpendicular circulation. The weakly cold air inflow boundary led to the convection. The montanic climate and cold air inflow from riverway made the warm air climb up. The airflow combinated with the perpendicular circulation made by relief. The important vapour source was the easterly jet on the second quadrant of typhoon ＂caidie＂ and on the bottom of subtropical high pressure belt. Vapour convergence was mostly on the lower troposphere. The convergence of wind direction and speed had been kept for a long time, and it resulted in the rain cluster stagnating. The potential vorticity disturbance of the upper troposphere was an important factor for the occurrance and development of the storm. The storm is accompanied with the high energy and high wet regions.

关 键 词：特大暴雨 台风 地形 多系统相互作用 

分 类 号：P461[天文地球—大气科学及气象学]