2010年前汛期末华南西部和东部暴雨对比分析  

Contrast analysis of a heavy rain at the end of the first rainy season in 2010 in west and east of South China

作　　者：张端禹[1] 崔春光[1] 赵玉春[1] 

机构地区：[1]中国气象局武汉暴雨研究所暴雨监测预警湖北省重点实验室,湖北武汉430205

出　　处：《气象与环境学报》2014年第6期8-15,共8页Journal of Meteorology and Environment

基　　金：公益性行业(气象)科研专项"华南持续性暴雨中尺度特征诊断分析和预报技术研究"(GYHY201106003);"风云卫星云微物理反演关键技术及应用"(GYHY201206003);"中尺度灾害天气短时(2-12小时)预报技术研究"(GYHY201006003);国家自然科学基金青年科学基金"江淮梅雨锋暴雨降水日变化的分析与模拟研究"(41105073)共同资助

摘　　要：2010年前汛期末期中国华南出现暴雨过程,暴雨在华南西部与东部有不同影响,利用NCEP再分析资料和常规观测资料,分析此次暴雨特征与机理。结果表明:对中国华南地区整体而言,暴雨期间高层受南亚高压东南伸弱脊辐散区影响;中层副热带高压西伸脊先东退、后西伸;暴雨区位于低层相当位温锋区南侧、气流辐合;边界层偏南风急流形成后暴雨发生。分区而言,华南西部两次出现各持续1 d的多站点暴雨时期;每次暴雨站数明显增加,较之前低层能量大、中低层层结不稳定且整层大气可降水量大;两个多站点暴雨日期之间边界层中尺度偏南风急流有两次明显减弱,低层水汽辐合与上升运动发生明显中断。华南东部多站点暴雨只出现一次但持续3 d,虽然在暴雨前期3个指数条件均没有西部两次暴雨前期好,但是连续3 d多站点暴雨期间较大尺度偏南风边界层急流基本维持,低层水汽辐合与上升运动没有发生明显中断,导致了东部暴雨站点多、强度大及持续时间长。因此,对于华南前汛期暖区暴雨而言,边界层偏南风急流的生消活动与水平尺度均较重要。A heavy rain took place at the end of the first rainy season of 2010 in the South China,and this process in the west was different from that in the east.By applying the NCEP reanalysis data,conventional observation da-ta,characteristics and mechanisms of the heavy rain were analyzed.The results show that as a whole,main influen-cing system at high levels over the Southern China is a weak ridge stretching southeast from South Asia High,and the air flow there is divergent.Middle level ridge stretching westward from Subtropical High retreats eastward first-ly,and then moves westward.Once boundary layer jet forms,the heavy rain appears in the south of equivalent po-tential temperature front at low level,and stream convergence takes place.For different divisions,the heavy rain occurs at many stations simultaneously twice in the west of South China,and it lasts 1 day every time.Averaged indexes calculated using the radiosonde stations data show that 850 hPa equivalent potential temperature and pre-cipitable water vapor are large,and stratification in the middle and low levels is very unstable before the number of stations with the heavy rain increases significantly in the west.Boundary layer jet weakens obviously twice over the west of South China between the two days when heavy rain takes place at many stations simultaneously.Between the two days of multiple heavy rain sites in the west,both upward movement and water vapor convergence in low level is interrupted obviously.It is only one time for the heavy rain event of many stations simultaneously in the east of South China,while it lasts for 3 days.The 3 indexes mentioned above are all not very favorable for the in-crease of number of heavy rain stations,although boundary layer jet maintains over the east of South China during the three days,and water vapor convergence and upward motion at low level are not interrupted.Thus this precipi-tation in the east is characterized with large areas,strong intensity and long duration.Generation or disappearance of southerly bou

关 键 词：华南前汛期暴雨 边界层偏南风急流 相当位温 沙氏指数 大气可降水量 

分 类 号：P458.121.1[天文地球—大气科学及气象学]