黄河中游一次中层低涡暴雨的中尺度数值模拟  

MESOSCALE NUMERICAL SIMULATION OF A MIDTROPOSPHERIC VORTEX WITH HEAVY RAINFALL OVER MIDDLE REACH OF YELLOW RIVER

作　　者：李小莉[1] 惠小英[1] 程麟生[1] 

机构地区：[1]兰州大学大气科学系,甘肃省兰州市730000

出　　处：《高原气象》1995年第3期305-313,共9页Plateau Meteorology

基　　金：85-906国家科技攻关项目:08-05;08-06;04-01课题

摘　　要：本文采用改进的MM4巾尺度模式模拟系统对造成1982年7月29日—8月2日黄河中游特大暴雨过程后一阶段强降水的低涡系统进行了中尺度数值研究。结果表明:与强降水密切相关的该中尺度系统是在登陆台风外围东南风急流影响下发展起来的具有斜压性的中尺度低涡,其风场上最强的气旋性涡旋在对流层中层。它并非登陆台风变性而成,而是由新生低涡发展而成的一个对流层中高层涡旋。造成暴雨中尺度低涡发展的主要机制是非绝热湿过程。凝结潜热释放在非绝热湿强迫中占主导地位。低涡发展时垂直运动与对流凝结潜热释放之间的正反馈过程是低涡持续发展、强降水发生的主要能量基础。地面热通量并非是决定暴雨中尺度系统发展的主要因子,没有地面热通量的贡献,大气的热力结构会受到影响,进而影响系统发展的强度,但系统的发展仍能维持,演变趋势不受影响。In this paper, we have investigated the mesoscale system, which caused the strong heavy rainfall event in the middle reach of the Yellow River during the late stage of July 29—August 2 1982, through mesoscale numerical simulations by using the improved MM4. The results show that the mesoscale vortex was not the result of transforming of the landing typhoon but the generating and developing mesoscale vortex under the influence of the peripheral southeast jet of the landing typhoon. It was a deep asymmetry midtropospheric vortex with clear baroclinic structure and strong warm advection at low level. The main mechanism caused the development of the mesoscale vortex was adiabatic moist process. Latent heat release was possessed of the dominant role in the diabatic moist force. The positive feedback between latent heat release and vertical motion was the essential energy source for the development of the vortex and the persistence of the heavy rainfall. The surface energy fluxes are not the decisive factor affecting development of mesoscale system. The thermal structure of model atmosphere was affected without the surface heat fluxes, in turn the intensity of development of vortex and precipitation were also affected; however, the development of mesoscale system was still maintained.

关 键 词：暴雨 中层低涡 中尺度 数值模拟 正反馈 黄河 

分 类 号：P458.121.1[天文地球—大气科学及气象学]