【摘要】 利用引入三相云显式降水方案后改进和发展的中尺度模式MM4模拟输出资料 ,对“96.1”暴雪过程的散度及其变率进行诊断分析。结果表明 ,低空辐合、高空辐散的散度场结构及其演变与暴雪切变线的生成发展及暴雪落区相对应。散度方程计算结果表明 ,低层散度负变率带及其内中心的生成与发展先于切变线辐合区的形成 ,揭示了暴雪降水系统的生成与发展 ,并与未来时刻的降雪强度及落区有较好的对应关系。更多还原

【Abstract】 The divergence and its variability during “96.1” snowstorm were diagnosed using the output data of the improved and developed mesoscale model (MM4), in which a three phase cloud explicit precipitation scheme has been introduced. The results showed that structure and evolution of divergence field with an intensive lower level convergence and upper level divergence were related to the genesis and development of the mesoscale shear line and snowstorm. By calculating the divergence equation, it indicated that the centers and their belts of the negative divergence variability in the lower level was formed and developed before that of the convergence with the strength and region of heavy snowfall 12 hours later.更多还原