东北冷涡诱发的一次MCS结构特征数值模拟  

A NUMERICAL STUDY OF THE MCS IN A COLD VORTEX OVER NORTHEASTERN CHINA

作　　者：陈力强[1] 陈受钧[2] 周小珊[1] 潘向党[1] 

机构地区：[1]中国气象局沈阳大气环境研究所,沈阳110016 [2]北京大学物理学院大气科学系,北京100871

出　　处：《气象学报》2005年第2期173-183,共11页Acta Meteorologica Sinica

基　　金：国家自然科学基金(40375020)

摘　　要：应用MM5模式对2002年7月12日东北冷涡诱发的强风暴进行了数值模拟,较成功地模拟出了MCS强对流风暴结构.东北冷涡南部锋区斜压扰动及有利的潜在不稳定层结为MCS产生提供了环境条件.MCS在发展阶段,天气尺度抬升使不稳定能量积累,低层中尺度能量锋区及中尺度气旋性环流加强使中尺度辐合加强,产生中尺度强上升气流冲破中层稳定层结,倾斜上升逐渐发展为垂直上升.MCS强风暴成熟阶段地面气压场表现为强的雷暴高压,并有弱的前导低压和尾随低压配合.对应于雷暴高压的边界层冷丘与南部的暖湿气流形成的θe不连续线加强了低层气流的辐合抬升.前导低压与800～700 hPa暖心低压扰动合并在一起,是由地面辐合、上升气流抽吸、潜热增温共同形成的低压扰动,对对流系统的维持和移动有重要作用.On 12 July 2002,a MCS initialed in a cold vortex over Northeastern China brought torrential rain over Liaoning province. This MCS was simulated successfully by Penstate/NCAR mesoscale model (MM5). The synoptic environment to MCS generation were provided by baroclinic disturbances and favorable potential instable layer of south front zone located on the northeastern cold vortex. In the development phase of MCS, meso-scale strong updraft produced by low-level meso-scale convergence which was caused by instable energy accumulation and meso-scale energy frontal zone in low layer and meso-scale cyclone circulation broke stable middle layer, and incline updraft gradually grow upright. In the mature phase of MCC, surface pressure field presented strong thunderstorm high and weak leading low and wake low. The discontinuity line between boundary layer cold dome corresponding thunderstorm high and southern warm wet flow strengthen convergence lifting. Combination of leading low and 800-700 hPa warm core low, which is disturbance of low pressure caused by surface convergence and updraft pump and potential heat warming, play important role to convective system maintaining and movement. After meso-high formed, the meso-scale convergence line which was produced by sinking outer flow and environment flow is the main flow convergence source of boundary layer cold dome affect the distribution of meso-scale temperature field and humidity field. The strong temperature grads and humidity grads are corresponding strong meso-scale wet baroclinic effects. Cold dome changed the atmosphere layer condition and this not only affect itself move but also affect other storm cell move and develop.

关 键 词：东北冷涡 数值模拟 MCS 结构特征 诱发 2002年7月 上升气流 MM5模式 强对流风暴 不稳定层结 中尺度辐合 中尺度气旋 地面气压场 环境条件 能量积累 天气尺度 能量锋区 成熟阶段 对流系统 强风暴 低压 扰动 压配合 不连续 

分 类 号：P433[天文地球—大气科学及气象学] TE319[石油与天然气工程—油气田开发工程]