东北地区一次积层混合云过程的数值模拟

积层混合云是中国主要的降水云型之一，它的动力和热力特征比单一的层状云或对流云都要复杂。利用NCEP的 1°×1°再分析资料，通过WRF模式对东北地区一次典型积层混合云过程进行数值模拟，通过对模拟结果分析并结合实际资料，从热力和动力方面研究了积层混合云的形成过程。结果表明：从稳定性上分析，此次过程属于潜在不稳定型，在积云初始生成时，对流有效位能并不大，假相当位温随着高度递减，有利于对流的发展；在积云嵌入大片层状云的过程中，水汽高低空辐合辐散场的变化起了决定性作用，热力作用为积层混合云过程提供了条件，动力因素起主要作用。

Numerical simulation on a convective stratiform in Northeastern China

The convective stratiform cloud is one of the main types of precipitation cloud in China,and its dynamic and thermal characteristics are more complicated than that of the single stratiform cloud or convective cloud. Based on the NCEP reanalysis data with 1°×1° spatial resolution, a typical convective stratiform cloud process in the Northeast China was simulated using the WRF model. The results show that this process belongs to a potential in- stability type according to an analysis of the stability. The convective available potential energy （CAPE） is not large at the initial phase in the formation of the convective stratiform cloud, and θse decreases with the height in- crease, which is favorable to the development of the convection. The change of water vapor convergence at the lower levels and divergence at the upper levels plays a dominant role when the convective cloud embeds the strati-form cloud. The thermal effect creates the conditions for this process and the dynamic factor plays a main role.