北京地区一次罕见的雷暴大风过程特征分析  

Analysis on an Exceptionally Strong Wind Gust Event in Beijing

作　　者：廖晓农[1] 俞小鼎[2] 王迎春[3] 

机构地区：[1]北京市气象台,北京100089 [2]中国气象局培训中心,北京100081 [3]中国气象局北京城市气象研究所,北京100089

出　　处：《高原气象》2008年第6期1350-1362,共13页Plateau Meteorology

基　　金：公益性行业(气象)科研专项经费项目"京津冀城市群强对流天气短时临近预报关键技术研究"(GYHY200706004);北京市科委项目"北京奥运会国际天气预报示范计划支持技术研究"(Z0006279040191)共同资助

摘　　要：分析了2006年6月24日北京地区一次罕见的瞬时极大风速超过32 m.s-1的雷暴大风事件。多普勒天气雷达观测表明,此次强雷暴大风与镶嵌在飑线回波带中的弓形回波相关。后侧入流急流促使飑线回波带南段快速移动并与其前面的新生单体合并加强形成弓形回波。深厚的中气旋、低层径向速度辐合和高层辐散等在构成弓形回波的强对流单体形成过程中起了重要的作用。根据雷达回波特征演变推断,这次雷暴大风直接由构成弓形回波的一个强对流单体内的下击暴流导致。使用微波辐射计和风廓线仪的观测资料揭示了上述强风暴发生的环境条件,即高的对流有效位能值、中等强度的风垂直切变,以及风切变的分布特征为飑线等的产生提供了有利条件。下沉对流有效位能和对流层低层环境大气温度直减率明显增加并接近干绝热,这对即将到来的下击暴流具有指示意义。An exceptionally strong wind gust process with maximum wind speed over 32 m · s^-1 appearing in Beijing on June 24, 2006 is analysed. The Doppler weather radar data show that the strong wind gust is caused by a bow echo which is a part of a squall-line. The bow echo comes into being correlates with the rear influx jet which leads to the acceleration of southern part of squell-line and then the squallline combines with the new-generation ceils in front of it. The deep meso-cyclone, the convergence at the low level and the divergence at the upper level play an important role in the development of the strong cell making up of the bow echo. Based on the observation of Doppler weather radar, it could be deduced that the strong surface wind is caused directly by the downburst inside. The microwave radiometer and profiler data are used in the analysis of the environmental condition about the instability and the vertical wind shear in the lower troposphere. The great CAPE, moderate vertical wind shear and the perpendicular wind dis- tribution are favorite to the development of the squall line. The increase of DCAPE and the temperature laps rate in the lower troposphere which is almost equal to the dry-adiabat are both indicate the downburst＇s coming.

关 键 词：北京地区 弓形回波 下击暴流 多普勒天气雷达 微波辐射计 

分 类 号：P458.121.2[天文地球—大气科学及气象学]