边界层辐合线对强对流系统形成和发展的作用  

The Role of Boundary Layer Convergence Line in Initiation of Severe Weather Events

作　　者：王彦[1,2] 于莉莉[1] 李艳伟[3] 朱男男[1] 高留喜[4] 

机构地区：[1]天津市气象台,天津300074 [2]中国气象科学研究院灾害天气国家重点实验室,北京100081 [3]南京信息工程大学,南京210044 [4]山东省气象台,济南250031

出　　处：《应用气象学报》2011年第6期724-731,共8页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(40975026);中国气象局关键技术集成与应用项目(CMAGJ2011M04);中国气象科学研究院灾害天气国家重点实验室开放基金(2009LASW-B04);公益性行业(气象)科研专项(GYHY200706004)

摘　　要：应用天津CINRAD/SA雷达探测到的边界层辐合线信息,对2008—2009年6—9月发生在天津地区的边界层辐合线进行了统计分析,与2002—2007年海风锋触发形成的局地强对流天气分析相结合,研究结果表明:天津地区边界层辐合线的雷达低仰角基本反射率因子产品的回波特征一般表现为弱的窄带回波,回波强度仅为15～25 dBZ,宽度一般为3～10 km。在合适的层结状态和水汽条件下,这些边界层辐合线的演变和碰撞与强对流天气的发生、发展密切相关。单一边界层辐合线一般不能形成大范围的雷暴天气;两条以上边界层辐合线之间碰撞,一般在碰撞交叉处能够形成强对流天气。若已存在强对流天气,则强对流天气将加强。CINRAD/SA Doppler Weather Radar can always detect weak and narrow echoes.Generally,those echoes can be closely associated with boundary layer convergence line,the feature and evolution of which may indicate the initiation of severe weather events.The data detected by Doppler radar from June to September of 2008 and 2009 in Tianjin areas,and the data on the events of sea breeze fronts from 2002 to 2007 are statistically analyzed.It shows that radar echo of boundary layer convergence line is also weak and thin,the intensity of echoes is 15—25 dBZ,and the width of echoes is 3—10 km.Boundary layer convergence line may be divided into three types,including sea breeze front,gust front and thin line due to special weather conditions.Single boundary layer convergence line may form isolated thunderstorm with favorable situation with moderate impact.The collision between boundary layer convergence lines can trigger thunderstorms or enhance the existing thunderstorms to be more severe. 56 and 44 sea breeze front cases are observed by radar in 2008 and 2009 respectively.The total number of 25 events of the initiation of severe weather events is closely associated with sea breeze front,including 17 events in 2008 and 8 events in 2009.The formation times of sea breeze front are different,the earliest time is 09：30,while the latest is 16：00.The sea breeze front＇s maintenance time is also of different length, the longest maintenance time is 6.5 hours,and the shortest is only 1 hour.The general distance that sea breeze front extends to the interior is 70—80 km,and the farthest distance reaches 120 km,with the height of 1.5 km in general.Those provide important information on the initiation of thunderstorms for nowcasts. 11 and 9 gust front cases are observed by radar during the observation period in 2008 and 2009 respectively. The maintenance time of gust fronts are inhomogeneous,with the longest maintenance time of 4.0 hours.Collision between sea breeze front and gust front can trigger thunderstorms.The boundary laye

关 键 词：边界层辐合线 强对流天气 雷达回波特征 海风锋 阵风锋 

分 类 号：P458.121.1[天文地球—大气科学及气象学]