一次飑线过程的雷达回波分析与数值模拟  

Radar Data Analysis and Numerical Simulation of a Squall Line

作　　者：慕熙昱[1] 党人庆[1] 陈秋萍 方德贤[1] 葛文忠[1] 

机构地区：[1]南京大学中尺度灾害性天气教育部重点实验室,南京210093 [2]福建省建阳市气象局,建阳354200

出　　处：《应用气象学报》2007年第1期42-49,共8页Journal of Applied Meteorological Science

摘　　要：2003年4月12日,一条飑线袭击了江西、福建、浙江三省,所到之处出现冰雹、大风等强烈天气,这次过程强度强,影响范围大,三省交界及附近区域有二十多个测站出现冰雹、大风,冰雹直径有的达3 cm以上,最大风速达32 m/s。该文利用建阳新一代天气雷达探测到的回波以及中尺度非静力数值模式(MM5)对这次过程进行数值模拟,分析此次强对流过程。结果表明:雷达回波显示出飑线的带状强回波,线状回波上呈现波型特征;在数值模拟结果中看到在系统发生的带状区域内有多个中尺度涡旋存在,在飑线内有中尺度涡旋簇和弓形回波。A squall line attacks Jiangxi, Zhejiang and Fujian provinces on April, 12 2003. The severe convective system leads to heavy damage, producing wind gust as large as 32 m/s, 30 mm diameter large hails in the affected area. This process is observed by the CINRAD in Jianyang City. The whole process of this convective system, including the initial stage, the developing stage, the mature stage and the dissipating stage, is analyzed. Many convective structures are observed in the process. At the location of the strong updraft, base reflectivity observed by mid-level elevation is stronger than the low-level and the high-level. This structure is called weak echo area. Corresponding to weak echo, there is a positive velocity area within a large negative velocity area in the mid-level. This structure is judged as mesoscale vortex sometimes by WSR-98D PUP. In fact, this phenomenon means the convergence in the target area, which is known as MARC （mid-level radial convergence）. Strong line echoes are observed in squall line by radar. It is well known that bow echoes that develop within a squall line are referred to as line echo wave patterns. In order to analyze the interior structure of the convective system, mesoscale numerical model （MM5V3） is used to simulate this process. In the control numerical simulation, reanalysis NCEP data（1°×1°） is used as the initial conditions. Radar observation data and simulation result are used to analyze the structure and the evolvement. Numerical simulation result confirms that the convective system takes place at the meeting of the northeaster and the southwester. There are many convective vortices and super cells within the 400 km system. Bow echoes appear near the vortices. There are obvious cyclones at the forehead of the line echo and divergence at the tail. Weisman indicates that in a mature bow echo cyclonic and anticyclonic vortices develop north and south respectively, in the channel of rear-to-front flow. These results resemble Weisman＇s study about squall lines in

关 键 词：强对流系统 雷达回波 弓形回波 中层径向辐合 中尺度涡旋 

分 类 号：P458.123[天文地球—大气科学及气象学]