Abstract:

By using conventional observation data and high density regional observation stations data, radar echoes and simulation results from the WRF model, an analysis about a local strong convective weather caused by weak cold air in mountainous area of the middle Shandong was done. The results show that the weather process occurred under the condition of unstable atmospheric state and the trough on 500 hPa was weak, and the influence of terrain in mountainous area couldn’t be ignored on triggering and strengthening the strong convection. The local convection was triggered easily at the northwest boundary of mountainous area, the middle scale low pressure center and maximum temperature gradient area. The simulation results of the WRF model show that the convergence caused by the flow around the terrain was favorable for convection strengthening, and the vertical circulation excited by windward slope was the main reason of the convection development. Under the weak environment field, when the convection was triggered, the strong radar echo would develop and strengthen along the high-energy zone of the ground.

Key words:  local convection, terrain triggering, underlying surface energy

摘要：

利用常规气象资料、区域加密观测站资料、雷达资料以及WRF模式输出资料，对一次漏报的受弱冷空气影响而引发的鲁中山区局地强对流天气过程进行诊断。结果表明，此次过程发生在500 hPa浅槽引导弱冷空气自对流层中层缓慢下沉造成气层位势不稳定的天气背景下，强对流在触发和加强的过程中复杂下垫面的影响有不可忽视的作用。局地对流易在山区西北边界的迎风坡、地面中尺度低压中心、温度梯度最大处触发；山区地形对垂直环流的激发是对流发展的主要原因；地形造成的近地面来自海上的东南风绕流辐合是对流加强的有利因素；在环境场较弱的情况下，局地对流触发后，强雷暴回波会沿着地面中尺度高能区发展、移动。

关键词: 局地对流, 地形触发, 地面能量