Numerical Study On The System Of The Stratiform And Embedded Convective Clouds In North China And The Conceptual Model Of Rain Enhancement Of These Clouds

The complex system of the stratiform and embedded convective precipitation is a main rainfall source in China. It is made up of the large-scale stratiform clouds and convective clouds embedded in the stratiform clouds. There are plenty of cloud water resources in the cloud. The clouds have their own unique structure of cloud systems. The dynamic characteristics and microphysical characteristics are different from stratiform clouds or convective clouds. When we study the complex system of the stratiform and embedded convective precipitation, we can know the clouds better. And the theory can instruct rain enhancement of the clouds.This paper is made up of four parts. First part gives the review of the system of the stratiform clouds and embedded convective clouds, and points out the urgent issues to be solved. Then, the paper gives an introduction of the WRF ARW model, especially the microphysical parameterization scheme and the cumulus parameterization scheme. In the third part of the paper, the thermo-dynamic structures and microphysical characteristics study on one case of a system of the stratiform and embedded convective precipitation on April, 18, 2009 is given in the paper. The precipitation mechanism of the clouds is also studied in the paper. In the fourth part of the paper, based on synoptic analyze, satellite image and simulation results, we study the thermo-dynamic structures and microphysical characteristics of the clouds on April, 20, 2010.At last, combining these two cases and other cases of 11th Five-Year, we classify these clouds, and give the conceptual model of rain enhancement of system of the stratiform and embedded convective clouds.The main results show that, the configuration of high-level trough, middle shear line, the ground front is propitious to the formation of cold front systems of the stratiform and embedded convective clouds. Strong updraft, because of high-level trough and middle-level trough, and plenty of water vapor are propitious to the formation of trough systems of the stratiform and embedded convective clouds. The system of the stratiform and embedded convective precipitation is different from normal stratiform or convective clouds. Some convective clouds radar echo is in the background of uniform stratiform clouds radar echo. The distribution of precipitation is non-uniform. Radar profile can reflect the adhesive mixed cloud structure across each other. When we study the development of structure of these clouds, the system of the stratiform and embedded convective clouds is made up of stratiform clouds and convective clouds. Stratiform clouds and convective clouds adhere each other, and then mix in horizontal direction. The liquid water content of the clouds is non-uniform. The maximum of cloud water and rain water correspond with maximum of graupel and ice. The mechanism of seeding-feeding and the mechanism of warm cloud coexist in the clouds. In the dynamic field, updraft exists in the centre of convective clouds, but downdraft exists in the side of the convective cells. Convergence is in the low level, while divergence is in the high level. The configuration is propitious to the development of the clouds. CAPE in 900hPa and ground is large, but CAPE is not large in the clouds. Thermal convection is not the main reason of the development of the stratiform and embedded convective clouds. Not only simple mechanism of seeding-feeding in stratiform clouds, but also circulation growth mechanism in cumulus clouds exists in the clouds. The particles of the stratiform clouds can exchange particles in convective clouds. The system of the stratiform and embedded convective clouds in North China can be divided into three categories: Clouds of mixed in horizontal direction, Clouds of open type flow fields and Clouds of stratiform connected with convective clouds. Based on temperature & humidity in clouds, concentration & phase state of particles, rain enhancement concept models have been brought forward. The best area for seeding is inflow current area of convective clouds filled with plenty of supercooled water at -5~-10℃...