摘要
用 ５００ ｈ Ｐａ 高度场资料及中国 １６０ 个站的月平均降水资料，采用 Ｅ Ｏ Ｆ、合成分析和奇异谱分析等方法，分析了长江中下游旱涝年夏季降水与同期东亚大气环流的关系，结果表明长江中下游旱涝与 ５００ ｈ Ｐａ 高度场东亚太平洋遥相关型（ Ｅ Ａ Ｐ）关系密切， Ｅ Ａ Ｐ指数能较好地反映夏季 ５００ ｈ Ｐａ 高度场的配置及长江中下游降水。文中重点讨论了 Ｅ Ａ Ｐ指数的振荡周期及高低指数年西太平洋副高的变化特征。 Ｅ Ａ Ｐ指数 ３～６ 年、准两年及年代际变化反映了长江中下游旱涝的年际变化及年代际变化趋势。 Ｅ Ａ Ｐ高指数年（对应涝年），西太平洋副热带高压为纬向型，随季节南北移动较缓慢，副高位置偏南偏西，并且强度偏强；而 Ｅ Ａ Ｐ低指数年（对应旱年），西太平洋副高呈经向型，随季节由西南向东北移动较迅速，副高偏东偏北，并且强度偏弱。
Based on the Northern Hemispheric 500hPa height and rainfall in China,study is performed of relations of the East Asia general circulation and rainfall anomalies in the middle lower reaches of the Yangtze river in terms of EOF,composites and SVD analyses.Results suggest that the EAP index has a close relartion with the system configuration of 500 hPa height field and the summer rainfall in the middle lower reaches of the Yangtze river.That is to say,in the flood (higher EAP index) years the general circulation at 500 hPa displays a typical EAP pattern with a strong West Pacific subtropic high south of 30 °N,while in the drought (lower EAP index) year,the West Pacific subtropic high is weak and lies north of 30 °N.The EAP index shows biennial,quasi 3 and quasi 6 year,and interdecadal variations,which also reflect well the interannual and interdecadal trends of flood/drought and 500 hPa height pattern over the middle lower reachds of the Yangtze river.
出处
《南京气象学院学报》
CSCD
1999年第3期312-320,共9页
Journal of Nanjing Institute of Meteorology
基金
国家自然科学基金
关键词
东亚-太平洋
大气
遥相关型
旱涝
副热带高压
East Asia Pacific Teleconnection Pattern
EAP Index
rainfall in the middle lower reaches of the Yangtze river
west Pacific subtropical high
