The above analysis showed that this heavy rainfall event took on obvious meso - scale characters and was the combination of the three flows , so we can deduce : ( 1 ) surface southeasterly wind and topography may play the main role in this event ; ( 2 ) the easterly cold air rushing into the southern shaanxi province in the lower troposphere was strongly relative to the form of surface cold - front type of occlusion ; ( 3 ) there were two reasons for the secondary circulation ' s strengthen in the evening , one was the effect of a mountain - valley wind and the other may be latent heat leading to ascending motion ; ( 4 ) the shape of potential instability stratification corresponded well with the development of the warm - moisture advection ; and ( 5 ) the vapor providing essential thermodynamics was transported by a southwesterly low - level jet from the bay of bengal and the south china sea . furthermore , with the effect of terrain , the southern shaanxi province became the center of this extremely heavy rain process 中尺度结构分析表明，本次暴雨具有明显的中尺度特征，是由三支气流共同作用的结果，分析发现( 1 )地面东南风和地形在这次大暴雨过程起主要作用； ( 2 )东路冷空气主要是通过中低层侵入陕南地区的，并与地面冷式锢囚锋的形成密不可分； ( 3 )夜博士论文:中尺度地形对陕南暴雨的影响研究间垂直次级环流发展加强可能有两个原因，一个是由于地形山谷风的作用，另一个是降水的潜热释放激发了上升运动: ( 4 )位势不稳定层结的形成与低层暖湿平流的发展有很好的对应关系; ( 5 )本次暴雨的水汽主要靠偏南风急流将孟加拉湾和中国南海的水汽输送至西北地区东部，为暴雨的发生提供了必要热力条件。
The persistent downpour in chifeng since the start of the rainy season has caused a severe flood disaster rarely seen in history . the heavy casualties and damage to personal possessions and local farming include 3 . 85 million acres of farmland submerged , over 70 , 000 houses destroyed , and 1 . 62 million people affected with more than 60 , 000 homeless 今年入汛以来，我市由于连降大暴雨，遭受了历史罕见的特大洪涝灾害，给人民群众生命财产和农牧业生产造成严重损失，致使385万亩农作物被冲淹， 162万人受灾，倒塌民房7万多间， 6万多人无家可归。
Using the pennsylvania state university ncar mesoscale model , a 36h simulation of the heavy rainfall process in hubei province on july 20 , 1998 is conducted . the simulation reproduced the evolution of meso - scale convective systems which were responsible for the heavy rainfall quite well . and the mcss visual images produced by the visualization software liveview can reveal the life cycle , the features of water materials distribution and 3 - d stream structure of mcs 用中尺度模式对1998 - 7 - 20湖北大暴雨过程进行了数值试验，较好地再现了中尺度暴雨系统的发展过程。利用大型可视化软件制作的中尺度对流系统的虚拟图像直观地展现了中尺度mcs群发生发展的生命史过程水物质分布的特点及其三维流场特征。
