中文摘要：

对2007年8月13日天津多普勒天气雷达（CIN RAD WSR/98D）探测的雷暴天气个例进行分析,结果表明：此次雷暴天气是由渤海湾海风锋与阵风锋碰撞形成的;碰撞后,在海风锋前端、阵风锋前部有新的雷暴单体形成;阵风锋后部的对流回波主体加强,对流回波主体由椭圆状加强为典型的弓状。应用天津36个自动气象站的地面六要素资料和北京850 h Pa以上探空资料,组成新的诊断资料,对该个例进行诊断分析,结果表明：雷达探测的海风锋前端具有较强的低层垂直风切变梯度和露点温度梯度大值区,海风锋前沿与0~3 km垂直风切变梯度密集区相对应,且与露点温度梯度变化较快的区域基本吻合;海风锋与阵风锋相互碰撞时,0~3 km垂直风切变在2 h内变化较快,且有明显的增加趋势,CAPE（convective available potential energy,对流有效位能）值在雷暴形成前有较明显增加;随着雷暴天气结束,上述特征随之消失。

英文摘要：

This paper studies a thunderstorm event detected by Doppler Weather Radar（ CIN RAD WSR /98D） in Tianjin on 13 August 2007,showing that the thunderstorm event is triggered by collision between sea breeze front and gust front over Bohai Bay. After the collided,new thunderstorm cells formed in the front of sea breeze front and gust front. The convection echo body intensifies in the back of gust front,and changes from theellipse echo to the typical bow echo. This paper applies the ground data of six factors at36 automatic weather stations in Tianjin and the sounding data above 850 h Pa in Beijing,forming new diagnostic data. Diagnostic analysis shows that there are strong low-level vertical wind shear and dew point temperature gradients in the front of sea breeze front detected by the Radar. The front edge of sea breeze front corresponds with the dense area of 0—3 km vertical wind shear gradient,and basically tallies with the rapid change zone of dew point temperature gradient. When the sea breeze front and the gust front collide,the 0—3 km vertical wind shear changes rapidly within 2 h with an obvious increasing trend,andCAPE（ convective available potential energy） has significantly increased before the formation of thunderstorm. With the end of thunderstorm,above features will disappear.