【摘要】 本文对湖南资水流域700hPa层呈现相似切变线天气形势的两次天气过程进行了研究,其中一次是2001年6月19日08BST出现大暴雨,另一次是2001年8月13日08BST至14日08BST仅出现小雨,文中对这两个个例进行中尺度数值模拟,对比分析了这两个个例演变过程的差异,并对6月19日中β尺度对流系统在暴雨强盛期的动力结构特征和热力结构特征作了详细分析。研究结果表明6月19日在演变过程中生产的中β尺度对流系统引发了这次暴雨,而8月13日虽然有类似于6月19日的切变线,但是没有形成中β尺度对流系统,也就没有引发暴雨。由此表明,相似的700hPa形势可以有根本不一样的演变,而暴雨的发生与中β尺度对流系统的生产和发展有十分密切的关系。更多还原

【Abstract】 Two cases of weather situation having similar shear line at the 700 hPa level and in Zishui river valley of Hunan province are studied by mesoscale simulations. Heavy rainfall area formed in the first case from 08BST 19 Jun. to 08BST 20 Jun. 2001, while in the second case only a light rainfall happened from 08BST 13 Aug. to 08BST 14 Aug. 2001. We analysis the dynamic and thermodynamic features of the meso-β-scale convective system which formed the heavy rainfall for the first case. In the second case, it appeared a shear line similar to the first case, but no meso-β-scale convective system occurred, so no heavy rainfall occurred. It implies that the occurrence of heavy rainfall depends on the occurrence and development of meso-β-scale convective system.更多还原