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投稿时间：2020-08-03 修订日期：2021-04-06
投稿时间：2020-08-03 修订日期：2021-04-06
中文摘要: 利用中国气象局地面站降水资料、欧洲中心ERA5再分析资料、FY-4A相当黑体亮温资料，分析了造成贵州水城2019年7月23日山体滑坡的大暴雨成因。结果表明，最强降水是由TBB低于-82℃的对流云带造成的，影响本次强降水的天气系统主要为贵州西部750~700 hPa低槽及四川盆地北部冷锋。暴雨发生之前，四川盆地北部冷锋迫使盆地内高能气团向贵州西北部移动。随着水城县鸡场镇南侧偏南气流发展，为强降水发生提供充足的水汽条件，同时因暖湿气流的增强使得鸡场镇低层对流不稳定性增强。降水初期（22日20时）上升运动主要位于700 hPa以下，这与鸡场镇地面偏东气流遇到地形阻挡、沿地形爬坡产生的上升运动影响有关。随天气尺度气旋性环流扩展到贵州境内，降水只发生在气旋性环流内较狭窄的带中。通过Barnes带通滤波分析，天气尺度的气旋性流场内存在一些小尺度的气旋、反气旋系统，鸡场镇西侧有两个小气旋环流，它们北侧的强气流汇合带正好是降水发生区，鸡场镇此时还位于一个小尺度鞍形场区域中，明显有利于中低层气流汇合，叠加地形性上升运动，导致突发性暴雨发生，造成了山体滑坡的形成。
中文关键词: 暴雨，山体滑坡，FY-4A
Abstract:Based on the precipitation data from China Meteorological Administration, ERA5 (the fifth generation of European Centre for Medium-Range Weather Forecasts Reanalysis) reanalysis data and the TBB (black-body temperature) data from FY-4A, the factors for the severe torrential rain causing landslide on 23 July 2019 were investigated. The results are as follows. The heaviest precipitation at 22:00 BT was caused by the convective cloud belt with TBB below -82℃. The synoptic systems were 750-700 hPa low trough and the cold front in the north of Sichuan Basin. Before the torrential rain, the cold front in the north of Sichuan Basin drove the air with large energy to flow from the basin to northwestern Guizhou. With the development of southern airflow in the south of Jichang Town, Shuicheng County of Guizhou Province, sufficient water vapor conditions were provided for the occurrence of the severe rainstorm. Meanwhile, the enhancement of warm and humid airflow made the convective instability in the lower layer of Jichang Town increase. At the beginning of the precipitation period (20:00 BT 22 July), the upward movement was mainly below 700 hPa, which was related to the influence of the easterly airflow that encountered the topographic obstruction and climbed along the slope of the terrain at Jichang Town. As the synoptic-scale cyclonic circulation extended into Guizhou Province, widespread precipitation occurred only in the narrow zones of the cyclonic circulation. After Barnes band-pass filter analysis, it is found that there were a number of small-scale cyclones and anticyclones in the synoptic-scale cyclonic flow field, and two small cyclone circulation on the west side of Jichang Town. The strong convergence zone on the north side of them was just the severe precipitation zone. At the same time, Jichang Town was also located in a small-scale saddle-shaped field region, which was obviously favorable for the convergence at low and middle levels, superimposed to the topographic upward motion. Therefore, the sudden severe torrential rain, resulting in the formation of landslides.
keywords: torrential rain, landslide, FY-4A
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基金项目:国家重点研发计划(2018YFC1507202)、国家自然科学基金项目(41975058、41620104009、91637211)、湖北省气象局科技发展基金项目（2018Y03）和湖北省气象局发展基金青年项目（2020Q02）共同资助
引用文本：
周文,王晓芳,杨浩,王婧羽,李山山,2021.造成贵州水城“7·23”山体滑坡的大暴雨成因分析[J].气象,47(8):982-994.
ZHOU Wen,WANG Xiaofang,YANG Hao,WANG Jingyu,LI Shanshan,2021.Causes Analysis of Severe Torrential Rain Inducing the Landslide in Shuicheng of Guizhou Province on 23 July 2019[J].Meteor Mon,47(8):982-994.
周文,王晓芳,杨浩,王婧羽,李山山,2021.造成贵州水城“7·23”山体滑坡的大暴雨成因分析[J].气象,47(8):982-994.
ZHOU Wen,WANG Xiaofang,YANG Hao,WANG Jingyu,LI Shanshan,2021.Causes Analysis of Severe Torrential Rain Inducing the Landslide in Shuicheng of Guizhou Province on 23 July 2019[J].Meteor Mon,47(8):982-994.
