淮北地区一次弱天气尺度强迫背景下MCS过程分析与模拟

利用多源观测资料和WRF中尺度数值模式对2016年8月7日淮北地区一次中尺度对流系统（Mesoscale Convective Systerm，MCS）过程进行诊断分析和模拟。结果表明，本次MCS过程发生在弱天气尺度强迫背景场下，系统性上升运动较弱，对流层低层存在较弱的源自西北太平洋的偏东风转东南风的水汽输送作用；MCS移动和形态变化与地面辐合线演变特征较为一致，地面流场的演变与降水强度之间有着密切的联系；WRF模式较好地模拟出本次降水的分布特征以及MCS演变过程中对流活动和地面辐合线相互作用的特征。模拟结果表明，本次过程中MCS在逐渐南移过程中完成了对流单体的更替，地面辐合线在此过程中发挥重要作用，并且处于不同发展阶段的对流单体环境场的对流不稳定度的垂直分布存在明显差异。

Analysis and simulation of an MCS process in Huaibei area against weak weather scale forcing

Based on the multiple observations and WRF model, a Mesoscale Convective System (MCS) process occurred on 7 August 2016 in Huaibei area was simulated and diagnostically analyzed. Results show that:firstly, the MCS process happens under weak weather scale forcing with weak systemic upwelling, coupling with weak water vapor transportation by the east to southeast winds, which originated from the Northwest Pacific Ocean in the lower troposphere. Secondly, the movement and deformation of MCS are consistent with the evolution characteristics of surface convergence line, and the evolution of surface flow field is closely related to the rainfall intensity.Thirdly,the distribution characteristics of precipitation and the interaction between convective activities and the ground convergence line during the evolution of MCS are reasonably simulated by WRF model. Finally, the simulation results indicate that the MCS has completed the replacement of convective cells during the gradual southward movement, meanwhile the surface convergence line plays an important role in this process. Besides, differences can be seen in the vertical distribution of convective instability in the environmental field of convective monomers at different stages of development.