中文摘要：

打破将散度演化分析局限于水平动力学框架内的传统认识思维,针对大气的斜压性与层结特征将对大气运动散度场演化产生显著影响的事实,从湿斜压原始方程出发,将大气的斜压热力作用通过热力学方程引入散度方程,在替换平衡近似（alternative balance）下,导出了显式包含湿非地转Q矢量与垂直风切变耦合强迫作用的新型散度方程.阐明了潮湿大气中非地转斜压强迫激发散度场演化的物理机制,为利用常规观测资料诊断散度场演化提供了一种有效的数学工具.通过对流层中低层气柱内总体辐合增长影响因子的分析,揭示了正压非平衡强迫、湿非地转Q矢量与垂直风切变耦合强迫激发辐合增长和暴雨维持的动力机制.进一步分析正、斜压强迫因子在暴雨过程不同阶段作用的差异性,提出了正压非平衡强迫是强降水天气过程启动机制,而湿斜压热动力耦合强迫是强降水天气维持动力机制的新观点.

英文摘要：

According to the occurrence and maintenance of torrential rain relating closely to moisture convergence increment in low layer of troposphere, factors affecting the evolution of divergence is analysed to reveal the dynamic mechanism of heavy rainfall maintenance. Starting from the primitive equations, we obtain a new type of divergence equation including the coupling forces between Q vector and vertical shear of wind. Analysis on this equation brings to light the main factors to influence the evolution of divergence. They are separately the barotropic non-equilibrium force and the baroclinic coupling forces between Q vector and vertical shear of wind. Especially, the evolution of divergence is only controlled by the above-mentioned two factors on the layer with the maximum convergence . In addition, the definite integral for new type of divergence equation is formed from the earth＇ s surface to the un-divergent level. Results show that the self-exciting process of divergence fields lead to the decrease of convergence in the low layer of troposphere. Oppositely, the barotropic non-equilibrium force and the baroclinic coupling forces between Q vector and vertical shear of wind are the main factors that promote the increment of convergence in the air column, which we should pay more attention to in studying the mechanism of heavy rainfall maintenance.