珠江三角洲附近地区强风暴的中尺度环境场若干特征分析

用滤波方法对两次强风暴天气过程进行尺度分离,得到与强风暴天气区相对应的中尺度扰动流场,分析结果表明:(1)强风暴天气—般出现在前期的层结不稳定区域内非热成风的大值中心附近。(2)在强对流的活跃阶段,在行星边界层的较下部和对流层的中部,分别有一无辐散层;从地面往上,辐散辐合依次相间出现;在强对流区的上空,存在明显的中尺度辐合和辐散中心。 此外,文中对中尺度扰动和强对流天气的成因作了初步讨论。 

ANALYSES OF CHARACTERISTICS OF MESOSCALE ENVIRONMENTAL FIELD OF SEVERE STORMS FOR THE PEARL RIVER DELTA AREA

The characteristics of mesoscale environment of severe storms over the delta are filtered in scaling to obtain mesoscale disturbances corresponding to effective areas of the storm weather. Analyses show that (1) severe storms usually occur near centers of maxima for non- thermal winds in earlier unstable atmosphere, and (2) during the active phase of severe convection,there is a layer of nondivergence at the lower levels of the PBL and mid-troposphere, respectively. From surface upward, divergent and convergent layers occur alternatively. Over the severe convective areas, there are well-defined centers of mesoscale convergence and divergence.In addition, causes responsible for the formation of convective weather are discussed in this paper preliminarily.