温带气旋诱发的渤海风暴潮天气分析

Weather analysis of Bohai sea storm surge caused by extratropical cyclone

通过对2007年3月4日渤海风暴潮天气过程进行分析,结果表明,强烈而持久的向岸大风是造成风暴潮的重要因素;气旋四周较强的气压梯度力是风暴潮的主要强迫动力;风应力增水作用与天文大潮相叠加直接加剧了风暴潮的强度;渤海特殊的地形特征有利于形成风暴潮天气,渤海地区风向的变化是导致渤海沿岸各地出现高潮位时间差的主要原因,当地面风由东北转为西北后,渤海湾的潮位开始回落,渤海海峡的潮位继续升高,其最高潮位出现时间与潮位回落时间均滞后于渤海湾;由于气旋的移动路径和影响时间造成渤海海峡的风速极值滞后于渤海湾,而其增幅却远远大于渤海湾。

Through weather analysis of Bohai sea storm surge cused by extratropical cyclone, the results show that： the intense and lasting easterly wind was the important factor;strong low level convergence and high level divergence made surface cyclone strengthened, pressure gradient force around the cyclone was the main dynamical force;the function of wind-stress increasing the water superimposed by the astronomy surge intensified the storm surge. The Bohai sea special terrain characteristic is advantageous to forming the storm surge, after the surface wind transfers from northeast to northwest, Bohai Gulf＇s tide level starts to recede, the Bohai sea channel tide level continues to rise, both the time of its highest tide position and the time during which the tide level recede tend to lag behind Bohai Gulf. The way of cyclone motion and its influence time made the time of wind velocity extremum of Bohai channel far lag behind Bohai Gulf, but the numerical value and amplitude exceeded Bohai Gulf.