地面辐合线演变与多尺度天气过程的相互作用分析

Interaction Between Surface Convergence Lines and Multi-scale Weather Processes

利用自动气象站、多普勒雷达和探空资料,对2012年7月4日山东半岛地区一次复杂天气背景下的地面辐合线演变过程及其与不同尺度天气过程的相互作用进行分析。结果表明:(1)3次天气尺度过程同地面辐合线发展演变关系密切,地面辐合线起源于渤海对流天气过程所产生的出流边界,辐合线深入内地成为鲁西北对流天气过程的触发系统,鲁西北对流过程和鲁南区域降水过程的产生又促使地面辐合线加强并转向北运动;(2)2次海陆和山谷局地热力环流过程促使地面辐合线南移发展;(3)风暴尺度对流过程与地面辐合线直接作用,首先地面辐合线与对流风暴的阵风锋对应,其次对流系统内多单体在地面辐合线的作用下整体向下游离散传播,而多单体的传播又造成雨带的快速移动。

By using high spatial and temporal resolution reanalysis products based on the ground stations, automatic weather stations and sounding data, as well as Doppler radar data,the interaction between surface convergence lines and multi - scale weather processes on 4 July 2012 was analyzed. The results are as follows ： （ 1 ） The three synoptic scale processes were closely related with the surface convergence lines. On the one hand, the surface convergence lines originated from the outflow boundary created by convection process over Bohai,and then they moved towards the mainland and became the trigger mechanism of convection process over northwest area of Shandong. On the other hand, the occurrence of convection process over northwest area and regional precipitation process in south region of Shandong strengthened the surface convergence lines and pushed them northward. （ 2 ） The land - sea wind and the mountain - valley local circulation strengthened the surface convergence lines and pushed them southward. （3） Storm convection process and the surface convergence lines had a direct interaction. Firstly, the surface convergence lines corresponded to the gust fronts. Secondly, multi - cells of convection systems propagated downstream, which caused the fast moving of the rain belt.