浙江“6．10”飑线过程中尺度分析  

The mesoscale physical analysis of "6.10" squall line in Zhejiang Province

作　　者：王东法[1] 沈杭锋[1] 高领花[2] 查贲[3] 周玲丽[1] 翟国庆[1] 

机构地区：[1]浙江大学地球科学系,浙江杭州310027 [2]浙江省台州市气象局,浙江椒江317000 [3]杭州市气象局,浙江杭州310008

出　　处：《浙江大学学报（理学版）》2009年第2期216-223,共8页Journal of Zhejiang University（Science Edition）

基　　金：浙江省重大科技攻关专项和社会发展重点项目(2006C13025);国家气象局高影响天气预报技术研究(07-107400-004);浙江省气象科技开发项目(KF006007)

摘　　要：利用雷达和地面加密观测资料对严重影响浙江省的一次飑线过程进行了中尺度分析,结果表明:在飑线的雷达回波出现前几小时,浙江西部的天目山和安徽黄山地区形成地面中尺度的地形汇合线和地面中小尺度的涡旋环流,地面的分析呈一种不连续的状况且易变化,飑线的发生发展一方面与低层的中尺度气流汇合线有密切关系,另一方面,也明显反映出老雷暴的外冲气流与前方的系统气流组成中尺度汇合线和辐合有关;这种地面中尺度汇合线上辐合强度十分明显,其垂直分布中,辐合主要发生在850hPa以下,由于高空槽线的前倾,位于飑线上空的对流层中低层是一辐散区.利用卫星云顶温度资料,可以发现主云区(TBB小值中心区域)与地面强风的辐散区对应,在辐散的前方出现7级以上的地面大风,可以达到强度为30m/s以上的偏北极值风,分析表明,云顶温度值随着飑线发展和地面大风的增强而有所减弱、TBB低温度区范围逐渐减小,但主云区范围扩大,这与飑线的发展和雷达回波图上扇形拉开相对应.从短时监测的资料分析,飑线发展过程中,雷达主回波前方的新生的回波单体对飑线发展和持续十分有利,而它的新生与边界层的辐合线相联系,因此,充分利用中尺度地面观测资料有助于飑线的发展研究.By the means of radar and intensive surface observation data, a mesoscale diagnosis is performed on the squall line which seriously influenced Zhejiang Province. The results show that the mesoscale confluent-line induced by terrain and surface mesoscale eddy appears a few hours before the radar echo in the areas of Tianmu Mountain in western Zhejiang Province and Huangshan Mountain in Anhui Province. The surface state is discontinuous. The initialization and development of the squall line is not only associated with mesoscale current confluent-line in low- level, but also related to mesoseale confluent-line and convergence induced by outflow of former thunderstorm and frontage system current. In the vertical direction,the convergent areas lie below 850 hPa while a divergent zone lie in low and mid-troposphere because of the forward tilting trough. According to satellite cloud top temperature data, it＇ s found that main clouds （low value of TBB area） were corresponding with divergent area of surface strong wind. The speed of north wind in the front of the divergent area can be larger than 30 m/s. The research indicates that TBB could be deduced as the development of the squall line and enhance of surface wind. According to short-term monitoring data, it appears that the new cell echo before the radar echo is advantage for the development and maintenance of the squall line. And the initialization of new cell is associated with boundary-layer convergence line. As a result, mesonet data is useful for to research on squall line.

关 键 词：飑线 地面中尺度分析 汇合线 地面大风 雷达回波 TBB分析 

分 类 号：P458[天文地球—大气科学及气象学]