2012年4月华南地区降水异常事件及成因诊断分析  

Abnormal Precipitation Event and Its Possible Mechanism over South China in April 2012

作　　者：王朋岭[1,2] 王启祎[1] 王东阡[1] 周兵[1] 

机构地区：[1]中国气象局气候研究开放实验室,北京100081 [2]中国科学院青藏高原环境变化与地表过程重点实验室,北京100101

出　　处：《地理科学》2015年第3期352-357,共6页Scientia Geographica Sinica

基　　金：国家重大科学研究计划(2012CB955901);中国科学院青藏高原环境变化与地表过程重点试验室开放课题项目(TEL201206);国家科技支撑计划项目(2009BAC51B02)资助

摘　　要：基于实时、历史观测资料和NCEP/NCAR再分析资料,采用气候统计和气候事件机理诊断分析方法,对2012年4月华南地区降水异常事件及其成因机制开展总结分析。结果表明:2012年4月华南大部地区降水异常偏多,强降水频发。华南地区降水异常事件的主要成因为:异常的高低纬环流形势配合,为华南地区降水异常偏多提供有利的环流背景,利于北方冷空气南下与西南暖湿气流在华南地区交汇;同期华南地区为异常偏强的上升气流控制,高低空辐散、辐合环流配置利于华南地区降水异常偏多;源自孟加拉湾、南海和西太平洋的异常水汽输送为华南地区提供良好的水汽条件,是华南地区降水异常事件的重要影响因子。Based on the daily real-time, historical observation data and NCEP/NCAR reanalysis data, the char- acteristics of abnormal precipitation event and possible mechanism in South China during April 2012 were ana- lyzed by the climatic statistics and climate event diagnostic methods. Results showed that the cumulative pre- cipitation amounts were observed evidently more than normal in most South China during April 2012, with the regional averaged precipitation amount ranking as the maximum value for the same period since the year of 2001. Moreover, the abnormal precipitation event caused rainstorm and flooding disasters in parts of South China. Taking above precipitation event as a case study from monthly time scale, key factors affecting the vari- ation of precipitation in the pre-summer flood season of South China were explored. The author analyzed sys- tematically the possible formation mechanism for the abnormal precipitation event in South China from the perspective of atmospheric circulation system anomaly and moisture transport. The major findings are as fol- lows： Firstly, The abnormal rainfall over South China during April 2012 was a direct result of contemporary at- mospheric circulation anomalies. The favorable atmospheric circulation pattern with positive anomaly of geo- potential height over the Ural mountain area and negative anomaly of geopotential height over most China and Mongolia, meanwhile, the South China Sea and northwest Pacific region controlled by abnormal anticyclonic circulation in the lower troposphere, benefited the cold air moving to South China and converging with the southly warm-wet air on South China. Thus the coordinated atmospheric circulation anomalies in higher lati- tude and lower latitude area provided favorable circulation backgrounds for the occurrence of abnormal precipi- tation event during April 2012. Meanwhile, most of South China was controlled by the atmospheric upward motions over the study period, with concomitantly divergence in upper-troposphere and convergence in

关 键 词：气候异常 环流异常 水汽输送 华南前汛期 机理分析 

分 类 号：P467[天文地球—大气科学及气象学]