【摘要】 本文对一次低空急流过程的数值模拟结果作了动力学分析,着重讨论了急流区的环流结构及积云对流对其发生、发展的影响。主要结果为:低空急流区有一对横向非地转二级环流,它是低空急流发展的一个重要条件;强频散的低空急流与积云对流造成的静力不稳定场耦合,诱发出不稳定的中尺度重力惯性波,通过Wave—CISK机制引导到低空急流与二级环流的发展;低空急流发展过程中的非地转特征和二级环流都是重力惯性波发展的产物。更多还原

【Abstract】 A dynamic analysis is made of the occurrence of a low-level jet stream with emphasis placed on the circulation structure in the jet region as well as the effect of the cumulus convection on its formation and evolution. It is found that a Couple of transversalageostrophic secondary circulations in the low-level jet region plays a significant dynamic role. The static instability field coupling caused by the strong dispersive Iowlevle jet and the cumulus convection induces unstable mesoseale gravitational inertia waves which trigger the development of the jet stream and secondary circulation through Wave-CISK mechanism. Both the ageostrophie characteristics and the secondary circulation in the evolution of the jet are the products of the development of the gravitational inertia waves.更多还原