热带太平洋次表层三维海温距平场的EOF分析  

EOF analysis of three-dimensional subsurface temperature anomaly field of the tropical Pacific Ocean

作　　者：张立峰[1,2] 许建平[2] 何金海[3] 

机构地区：[1]杭州市气象局,浙江杭州310008 [2]卫星海洋环境动力学国家重点实验室,国家海洋局第二海洋研究所,浙江杭州310012 [3]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《海洋学研究》2008年第3期35-43,共9页Journal of Marine Sciences

基　　金：国家科技部国际合作重点资助项目(2002CB714001);国家海洋局青年基金资助项目(2004203);卫星海洋环境动力学国家重点实验室资助项目

摘　　要：应用太平洋次表层海温距平资料构造了一个立体的西低东高的四级阶梯模型,使用EOF方法对此模型进行时空分解,重点讨论了分解结果与ENSO循环的关系,并对Nino 3距平指数进行试预报,结果表明,用EOF分解的第一主分量代表暖池-厄尔尼诺(拉尼娜)模态,第二主分量代表次表层温度距平的东西运移模态,厄尔尼诺事件正是东西运移模态突变的结果。时滞相关分析估算,一次ENSO循环的平均周期约为41个月,厄尔尼诺、拉尼娜模态与温度距平的东西运移模态的位相差平均约为9.7个月。应用逐步回归方法得到超前Nino 3距平指数3、6和12个月的3个预报方程。预报结果表明,第一、第二时间系数对Nino 3距平指数均具有一定的预报价值,预报时效可达1 a左右。A three-dimensional four-step sea temperature model low in the west and high in the east has been formed with the subsurface temperature data of the tropical Pacific Ocean. The first step is between 120° to 180°E,with the average subsurface departure between 120 m and 160 m. The second,third and fourth steps are between 175° and 140°W,135° and 120°W,115° and 80°W respectively,with average subsurface departures between 80 m and 120 m, 60 m and 80 m,and 40 m and 60 m. The whole longitude ranges is from 120°E to 80°W,while the whole latitude range from 18°N to 16°S. The steps are close to the climatic thermocline,which contains not only the horizontal field information but also possible perpendicular profile information. Empirical orthogonal function（EOF）is used to make time-space division of this model matrix. And the relationship between EOF division result and ENSO cycle is discussed,and the Nino 3 departure index is predicted. It shows that accumulated variance contribution of the first and second spatial characteristic principal components in EOF division reaches 42.58% ,among which the first one represents tropical Pacific warm pool- El Nino and Lanina mode and the second one represents the east-to-west movement mode of the subsurface temperature departure in the tropical Pacific Ocean. There are catastrophe and gradual change processes in the latter. The change from the cold phase to warm phase near the equator is gradual, while the change from the cold phase to warm phase near 10°S or 10°N is catastrophe. El Nino（Lanina）results from the catastrophe change of the east to west movement mode. Time lag correlation analysis and estimation of the first and second time coefficients of the EOF division and the Nino 3 sea temperature departure indexes shows that the average circulation cycle of the tropical Pacific subsurface temperature departure is 41 months,namely 3.42 years,and the phase difference between the east to west movement mode of the tropical Pacific subsurface temperature departu

关 键 词：次表层海温距平 阶梯模型 ENSO循环 热带太平洋 

分 类 号：P732.5[天文地球—海洋科学]