2007年梅汛期异常降水的大尺度环流成因分析  

Causes Analysis of Abnormal Rainfall and Its Large-scale Circulation During 2007 Meiyu Season

作　　者：金荣花[1] 陈涛[2] 鲍媛媛[2] 王秀文[2] 张芳华[2] 

机构地区：[1]中国气象科学研究院 [2]国家气象中心

出　　处：《气象》2008年第4期79-85,共7页Meteorological Monthly

基　　金：国家气象中心2007年极端降水事件成因分析及预报服务技术研究项目

摘　　要：为深入理解江淮梅雨持续性强降水的大气演变过程,探讨中期预报技术途径,利用NCEP/NCAR逐日再分析数据和历史梅雨特征指数等资料,系统地分析了2007年梅汛期异常降水的大尺度环流成因。结果表明:梅汛期,西北太平洋副热带高压稳定和7月中下旬持续偏南,决定了2007年梅汛期降水的时间和地域分布特征。阻塞高压的频繁出现和副热带季风涌的异常强盛为梅雨锋维持和加强提供了有利的动力、热力以及水汽条件;"伊朗型"南亚高压的活动以及东亚上空副热带急流通过高低空耦合动力作用,不仅为持续性暴雨创造了良好的垂直环流结构,也间接抑制了副高北抬。在此研究基础上,归纳出中期预报着眼点,供实际业务预报参考使用。Using daily NCEP/NCAR reanalysis dataset and the historical Meiyu feature index etc., the causes of abnormal rainfall and its large-scale circulation during 2007 Meiyu season are analyzed in order to better understand the evolvement characteristics of persistent rainfall and its atmospheric circulation on Jiang-Huai Meiyu, and to discuss technical approaches of mid-range forecast. The results show that the stability of the western Pacific subtropical high located in the south more persistently than normal in middle-late July during Meiyu season plays a crucial role in the temporal and spatial characteristics during 2007 Meiyu period. The frequent appearance of blocking high and abnormal strong subtropical monsoon surge provide favored dynamic, thermodynamic and moisture factors affecting maintenance and intensification of Meiyu front. The activity of ＂Iran type＂ south Asia High and upper-low level coupling dynamic action of subtropical jet in East Asia not only create favorable vertical circulation structure for persistent heavy rainfall but also restrain northward movement of subtropical high. At last, the keys of mid-range forecast are summarized on the basis of these results.

关 键 词：梅汛期 异常降水 大尺度环流特征 成因分析 

分 类 号：P458.121.1[天文地球—大气科学及气象学] P429