【摘要】 采用多种常规和非常规资料对2004年9月3—6日形成川渝暴雨过程的中尺度对流系统及其发生发展的背景场进行分析后认为:(1)低涡切变线上不断发生发展的中β尺度对流系统是造成此次强降水的主要原因;(2)高层强辐散与中、低层强辐合以及强上升运动可能为中尺度对流系统的发生发展提供了有利的动力背景;(3)水汽通量的强辐合以及对流不稳定条件的存在可能为中尺度对流系统的发生发展提供了有利的热力背景。更多还原

【Abstract】 Based on the routine and non-conventional data, mesoscale convective systems and backgrounds causing heavy rain in Sichuan and Chongqing during 3—6 September 2004 are analyzed. It is found that (1) the reason for heavy rainfall is meso-β scale convective systems, occurred and developing frequently on the low vortex and shear line, with local and explosive features occurred and developed in the Sichuan Province and Chongqing City; (2) the lower-level convergence and upper-level divergence and vertical ascent motion probably provided the suitable dynamic environment for the generation and development of the mesoscale convective system; and (3) strong convergence of water vapor flux and the conditional convective instability in the lower troposphere probably provided the suitable thermodynamic environment for the generation and development of the mesoscale convective system.更多还原