Based on the intensive automatic weather station and radar wind profiler data with high temporal and spatial resolution, the mesoscale observational characteristics of three short-duration rainstorm processes in Xingtai city are analyzed. The short-duration rainstorm was produced under the favorable large-scale circulation background. The lower layer shear system, strong vertical wind shear between middle and low levels, surface low pressure and inverse trough were the favorable conditions for convergence and ascending motion. The warm wet air flow from southwest interacted with the cold air from the westerly winds and northeast backflow. The surface mesoscale shear was the trigger system, whose position was consistent with the intensive precipitation area. The intensive precipitation corresponded to the beginning, duration, and strength of east winds in the boundary layer. The surface ascending east-winds were forced by the convergences resulted from the topographic forcing, and so the mesoscale convergence system was strengthened. The urban atmospheric thermal forcing and topographic effect triggered jointly the urban short-duration rainstorms.%通过对2009年5月9日、2007年7月18日和2006年8月28日邢台市3次城市短时强降雨过程的对比分析,应用高时空分辨率的加密自动站资料、雷达风廓线资料,研究其中尺度特征.强降水天气产生在大尺度有利的环流背景下,低层切变线系统、强中低空垂直风切变、地面低压倒槽提供了有利的辐合上升动力条件,低层西南暖湿气流与西风带冷空气以及边界层东北急流带来的回流冷空气相互作用,为强降水提供了有利的热力和不稳定层结条件.地面中尺度切变线是强降水的触发系统,强降水落区与地面中尺度辐合系统位置一致,地面和边界层偏东风的开始和持续时间、强度与强降水有很好的对应关系.边界层偏东气流由于西部山脉的地形作用在山前汇聚从而强迫抬升,使地面中尺度的辐合系统产生和加强,城市热力强迫与地形的共同作用触发城市强降水的产生.
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