【摘要】 利用NOAA的逐月平均SST资料和NCEP/NCAR的逐月平均500 hPa高度场资料,采用非线性典型相关分析(NLCCA)分析了冬季热带太平洋SSTA场和太平洋北美地区500 hPa高度距平场之间的非线性关系,结论得出:NLCCA有能力表示出更一般的低维结构,可以提取资料集中传统CCA所不能提取的特征。NLCCA第一模态的典型相关变量μ从最大值变化到最小值,重建的SSTA场从强El Nino位相变换到强La Nina位相。La Nina位相的负距平中心(100°W左右)比El Nino位相的正距平中心(150°W左右)偏西约50个经度。对于500 hPa高度场,其非线性特征主要表现为定常波列(Rossby波)的位置偏差。El Nino时,PNA正位相的四个距平中心比La Nina时PNA负位相距平中心位置向东偏离约20个经度。NLCCA所得结论与合成分析结果一致。更多还原

【Abstract】 Based on the monthly average analysis data of SST by NOAA and monthly average 500 hPa height reanalysis data by NCEP/NCAR,the nonlinear relationships of tropical Pacific SSTA and 500 hPa height field over Pacific north America during winters are determined with the technique of NLCCA.The results show that NLCCA is able to characterize the more general low-dimensional structures than CCA.It can detect the characters that traditional CCA can not do.When u variates from high to low,the reconstructed SSTA is evolving from El Nino to La Nina.The center of La Nina(around 100 °W)is 50° westward to the one of El Nino(around 150 °W).To the 500 hPa height field,the nonlinearity is largely due to a phase shift of the stationary wave anomalies.The four anomalies of PNA for El Nino are 20° eastward to the ones of PNA for La Nina event.The conclusions of NLCCA are consistent with the ones of composite analysis.更多还原