2007年华南一次强飑线过程的雷达回波分析及数值模拟  

Radar Data Analysis and Numerical Simulation of a Strong Squall Line in South China in 2007

作　　者：陈业国[1] 沈桐立[2] 唐文[1] 

机构地区：[1]广西气象台,南宁530022 [2]南京信息工程大学,南京210044

出　　处：《暴雨灾害》2008年第2期135-140,共6页Torrential Rain and Disasters

基　　金：广西自然科学基金项目(桂科攻0632006-1D)资助

摘　　要：2007年4月17日华南发生了一次强飑线天气过程。利用常规气象资料、多普勒雷达资料分析了这次强飑线过程的成因,并用高分辨率中尺度数值模式WRF对该过程进行数值模拟。结果表明:这次强飑线过程发生在欧亚中高纬地区两槽一脊的经向环流形势下,西风槽、地面冷锋为其主要的影响系统。雷达回波显示,这次强飑线过程的雷达回波具有典型的三体散射和弓形回波特征。此外,WRF模式能成功地模拟出本次飑线过程的中β尺度结构特征。数值模拟结果显示,飑线发生的带状区域内有明显的低层气流汇合和切变以及中低层的大气对流性不稳定结构,强对流带内有东北-西南走向的气流汇合线,汇合线附近有强的辐合,辐合中心强度达-0.8×10-3 s-1,表明WRF模式对强对流天气系统有一定的模拟能力。A strong squall line attacks South China on April 17,2007： By using the conventional observations and Doppler weather radar data, this strong squall line process is analyzed with the situation and the evolution characteristics of the radar echoes. The mesoscale numerical model WRF （Weather Research and Forecast） is used to simulate this process for the interior structure of the convective system. The results show that this strong squall line event occurs in the circulation background of two troughs and a ridge over the middle and high-latitude regions of Europe and Asia mainly impacted by the westerly trough and surface cold front. The strong squall lines are the radar echo characteristics of a typical three-body scattering and the bow echo. The strong convection in the region of three-body scattering and the bow echo is very obvious. There are many convective vortices and super cells in the system when the strong squall line hit the noah and middle part of South China. Bow echoes appear near the vortices. There are obvious cyclones at the forehead of the line echo and divergence at the tail. In addition, meso-β scale structure characteristics of the strong squall line process are successfully simulated. Simulation results show that there are obvious convergence, shear and convection unstable structure at the low layer in the squall line zone, the northeastward airflow convergence line in the strong convection zone is closed by the strong convergence region with the center intensity of 0.8×10^-3 s^-1.

关 键 词：飑线 中β尺度 数值模拟 

分 类 号：P458.2[天文地球—大气科学及气象学]