利用多普勒雷达、地面自动站、垂直风廓线及GPS水汽分布等多种新型探测资料,对2008年8月14日下午,奥帆赛期间发生在青岛地区的局地大暴雨天气的影响系统和中尺度强降雨形成的动力机理进行了综合分析,并通过0.5 kmWRF模式的数值模拟给出了有地形阻挡情况下海风环流模型。研究结果表明:副高减弱东撤和弱冷空气南下在中低空形成闭合低涡是造成这次过程的主要天气尺度影响系统。海风中尺度辐合带上有风向切变辐合、大暴雨中心有明显的雷暴高压等中尺度天气系统。海风锋区辐合扰动向上传播,引发边界层扰动,是青岛局地大暴雨形成的主要抬升因素,而来自东南海洋上的暖湿平流为大暴雨的产生提供了充沛的水汽和能量。海风锋区辐合带上触发的强对流是大暴雨形成的直接原因;来自于海上的低空急流带来的大量水汽对强降雨的发生具有重要作用。海风在深入陆地后所发生的辐合和上升运动,对造成海风所触发的局地大暴雨有着极其重要的作用。

A local torrential rain process occurred on the 14th August,2008 and its dynamic mechanism were analyzed synthetically by using Doppler radar data,automatic station data,wind profile data and GPS vapor distribution.The modeling of WRF with a horizontal resolution of 0.5 km simulated the sea breeze circulation under the influence of topography.The results indicated that the torrential rainfall process was affected mainly by the subtropical high retreating easterly and closed low vortex at low and medium level,which was formed due to weak cold air moving to the south.There were wind shear convergence along the sea breeze frontal zone and thunderstorm high pressure around the center of torrential rainfall.The boundary layer perturbation produced by the sea breeze frontal convergence was main uplift element and warm and wet advection from southeast sea supplied ample water vapor and energy to the rainstorm.The severe convection triggered by the sea breeze frontal convergence was the direct cause of the torrential rainfall and the low level jet from the sea with abundant vapor played an important role on the torrential rain.The sea breeze extending to the inland resulted in convergence and ascending motion and then played an important role on the torrential rain which was induced by see breeze.