近50a江苏梅雨量异常的时空分布及其环流特征  

Temporal and spatial distribution and circulation features of the Meiyu precipitation anomaly in Jiangsu in the latest 50 years

作　　者：孙燕[1] 尹东屏[1] 姚丽娜[1] 曹舒娅[1] 

机构地区：[1]江苏省气象台,南京210008

出　　处：《暴雨灾害》2012年第2期149-154,共6页Torrential Rain and Disasters

基　　金：江苏省科技厅科技支撑计划社会发展项目(BE2011818);淮河流域气象开放研究基金(HRM201006);江苏省气象科研开放基金(K201006)

摘　　要：利用1961—2009年江苏66站逐日降水资料和NCEP/NCAR逐日再分析资料,采用EOF分解、小波分析、合成分析等方法,探讨近50 a江苏省梅雨量异常的时空变化和环流特征。结果表明,江苏梅雨量存在全区一致型、南北(以32°N为界)反位相型、江淮之间与淮北及沿江苏南反位相型三种主要空间型;江苏梅雨量异常均存在显著年际变化和年代际变化特征,并存在准2 a、准4 a和准6 a的振荡周期;近50 a江苏梅雨量呈一致的增长趋势,且淮北地区和苏南地区的正趋势明显,通过置信水平为95%的检验。此外,江苏丰梅年份,南亚高压中心偏东,强度偏弱,面积偏小;副热带高压西伸脊点偏东,588 dagmp线北界偏北,面积偏大;东北冷涡活动频繁,引导干冷空气南下,与强盛的西南暖湿气流相互作用,冷暖气流在江苏交绥,梅雨量偏多。枯梅年环流形势则与之相反。Based on daily precipitation data from 66 stations in Jiangshu province from 1961 to 2009 and the NCEP/NCAR reanalysis data, Empirical Orthogonal Function （EOF）, Morlet wavelet analysis and composite analysis methods were used to investigate temporal and spatial change and circulation features of the Meiyu precipitation anomaly in Jiangsu in the latest 50 years. The results show that the Meiyu precipita- tion in Jiangsu presented 3 main spatial patterns, i.e., the consistent pattern in the whole region, the spatial reverse pattern between the north and south （bordered by 32°N） and the spatial reverse pattern among the Yangtze-Huaihe River region and other regions in Jiangsu. Anoma- lous Meiyu precipitation in Jiangsu has the significant inter-annual and decadal change, presenting quasi-two-year, quasi-four-year and quasi-six-year periodic oscillation. Meiyu precipitation in Jiangsu in the latest 50 years presents a trend of increase and presents obviously positive trend in Huaibei and the southern part of Jiangshu province with over 95% confidence level. In addition, South Asia high has an east- ward central zone, weaker intensity and smaller area; but subtropical high moves westward and the ridge point is easterly, 588-dagpm isoline is northward and area is bigger; the dry and cold air led by the Northeast China cold vortex moves southward and interacts with strong south- west warm and wet airflow in Jiangsu resulting in precipitation more than that in the same period of normal years in all High Meiyu years. The circulation patterns in all Low Meiyu years are contrary to the patterns mentioned above.

关 键 词：梅雨量异常 环流特征 EOF分解 小波分析 合成分析 

分 类 号：P458.121[天文地球—大气科学及气象学]