2014年3月广东一次飑线过程观测及数值模拟分析  

Observation and Numerical Simulation Study of a Squall Line Process

作　　者：缪子青 何宏让[1] 白仕刚 汤鹏宇[1] 

机构地区：[1]解放军理工大学气象海洋学院 [2]解放军96219部队 [3]解放军96319部队

出　　处：《气象与减灾研究》2014年第4期7-17,共11页Meteorology and Disaster Reduction Research

基　　金：国家自然科学基金项目(编号:41375106)

摘　　要：对2014年3月31日广东省一次飑线过程进行了观测资料分析和数值模拟研究。观测资料分析表明:飑线发生在强低空垂直风切变和"上干下湿"的水汽垂直分布的环境条件下。在强盛阶段,飑线上的对流单体多表现为强降水超级单体,有明显的有界弱回波区(BWER)和回波悬垂结构。飑线前沿有明显阵风锋,后侧有弱回波通道,弱回波通道和后侧入流急流(RIJ)相对应,RIJ维持时间较长,对"弓"形回波的形成、地面大风、飑线的维持和快速移动具有重要的作用。模式输出的高分辨率资料分析表明:在减弱阶段飑线移入残留的冷池中,冷池得到加强,此时西南暖湿气流加强,飑线二次发展。成熟飑线的三维结构表现为低层为2支入流、高层为2支出流,且前侧出流速度较快,使得气流倾斜上升,容易形成悬挂回波和弱回波区(WER)。后侧入流下部(600 h Pa高度层以下)的辐散下沉气流是地面大风形成的原因。对流两侧的"涡旋串"(Vortex bunch)对冷暖空气加速入流、对流发展强度和高度以及对流的长时间维持有很大的作用。A squall line process occurred on 31 March 2014 in Guangdong was analyzed by using the observed data and the numerical simulation model. The result shows that the squall line occurred in the environmental conditions of the strong low-level vertical wind shear and the upper level dry vapor. During the strong stage,the convective cells in squall line characterized by heavy precipitation supercell with a bound weak echo region（BWER） and an echo overhanging structure. The forefront of squall line had an obvious gust front and a weak echo channel in the back side, a weak echo channel was corresponded to the sloping rear inflow jet（RIJ）accompanying a long time maintenance, which played important roles in the formation of the ＂bow＂ echo, the maintenance and fast moving of the surface wind and the squall line. According to the analysis of high resolution data of the model output, it showed that the squall line moved into the residual cold pool lead to strength of the cold pool during the weakening stage. At this time, the squall line presented a secondary development due to the southwest warm wet current strengthening. The three-dimensional structure of mature squall line showed that there were two branches of inflow at the low level with two expenditure flow at the high-level. It was easy to form the suspension echo and weak echo region（WER）. Divergence downdraft airflow in the lower level of rear inflow（below 600 hPa）was the reason of the formation of the ground wind. The ＂Vortex bunch＂ on both sides of convection also had great effects on the accelerated inflow of cold and warm air, the height and strength of the convection development and the long-term maintenance of convection.

关 键 词：飑线 数值模拟 雷达回波 后侧入流急流 冷池 

分 类 号：P445[天文地球—大气科学及气象学]