Analysis on A Mesoscale Convective System in North China Plain
Lü Sheng-hui;GAO Yan-hong;LIU Wei
Author information+
Tianjin Air Traffic Management Station of CAAC, Tianjin 300300, China;2. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China;3. Lanzhou Air Traffic Management Center of CAAC, Lanzhou 730087, China
Meteorological routine observation data are used to analyze a Mesoscale Convective System (MβCSs) on the Meso-β scale which takes place in the North China Plain on June 1, 2002. The results show that the convective system occurs in the wind shear zone, and it locates on the right-hand side of upper-level jet stream, and which exists in the northeast part of North China Plain, due to the influence of the Northeast Cold Vortex. The collective effect of upper-level positive vorticity advection and low-level negative vorticity advection results in both upper-level convergence and low-level divergence, which tend to maintain the ascending motion of middle troposphere in this region. Low-level moisture flux convergence provide plenty of water vapor. Then decreasing(increasing) the total energy of the upper(low)-level airso that a large amount of unstable energy develops over the North China Plain. This circulation pattern favors convective systems and finally triggers the mesoscale convective system. This paper sheds light on the causes of MβCSs and provides some experiences for forecasting MβCSs in the future.