两个路径相似台风暴雨过程的模拟分析  

ANALYSIS OF A SIMULATION OF HEAVY RAINFALL ASSOCIATED WITH TWO TYPHOONS WITH SIMILAR ROUTES

作　　者：张建海 于忠凯 何勇 

机构地区：[1]绍兴市气象局,浙江绍兴312000 [2]诸暨市气象局,浙江诸暨311800

出　　处：《热带气象学报》2010年第4期392-400,共9页Journal of Tropical Meteorology

基　　金：浙江气象科技开放研究专项(Kf2006009)资助

摘　　要：以两个路径相似的台风"海棠"和"凤凰"为研究对象,利用MM5模式对其二次登陆过程进行模拟并通过与实况的对比表明,模式对台风路径和暴雨的模拟是成功的。利用模式输出从动力、水汽、不稳定层结和地形等四方面对暴雨落区和强度进行诊断,结果表明:低层螺旋度正值区与未来12 h暴雨落区有良好对应关系,高层螺旋度负值区偏离暴雨区,螺旋度高低层耦合产生的倾斜上升气流是触发和维持台风暴雨的动力机制。在台风登陆过程中,浙南闽北一直有源源不断的水汽输入,登陆点北侧水汽输送大于南侧是造成台风降水非对称分布的重要原因。台风由暖洋面移入大陆"冷场"加强了不稳定层结,在"海棠"台风暴雨过程中,弱冷空气侵入台风环流,触发不稳定能量释放在暴雨增幅中起了重要作用,暴雨出现在相当位温等值线密集的向北倾斜锋区。地形对暴雨的增幅作用十分显著,迎风坡由于地形动力抬升有利于上升运动加强,使得对流发展旺盛,降水增加,形成暴雨中心。The second landfall process on China's Mainland of two typhoons with similar routes, Haitang（0505） and Fungwang （0808）, were simulated by using the MM5 model and the routes and distribution of the heavy rainfall associated with typhoons were successfully reproduced. Then a diagnostic analysis was carried out to gain a better understanding of the heavy rain mechanism by using the model output data from viewpoints of dynamic structure, moisture transport condition, unstable stratification and topographic effect. The results show that the positive center of helicity at lower levels can reflect the position and intensity of the rainstorm in the successive 12 hours and the area of helicity is negative at upper levels, which is deviated from where the rainstorm is, and a tilt updraft coming from couplings between the upper level and lower level of helicity is a dynamic mechanism for the production and maintenance of the heavy rain and favorable for the sustaining of typhoon＇s spiral structure. During the landfall, the specific moisture transport offered abundant water vapor to areas south of the Zhejiang province and north of Fujian province and the phenomenon of more rainfall at the north side of the landfall site of the two typhoons was also in connection with the amount of moisture transport. Meanwhile the cold characteristic of air mass over Zhejiang was also a favorable factor for the heavy rain of the two typhoons, deeply reinforcing the unstable stratification. Weak and cold air played a great part in increasing the heavy rain of Haitang, which invaded its circulation and motivated the release of unstable energy. The torrential rain was located at a frontal zone of equivalent potential temperature, which inclined northward vertically. The topography increases the rainfall significantly on the windward side while deceasing it on the lee side.

关 键 词：台风暴雨 数值模拟 螺旋度 冷空气 地形影响 

分 类 号：P426.62[天文地球—大气科学及气象学]