PDO的三维空间结构和时间演变特征

3-D spatial structure and temporal evolution features of PDO

利用再分析次表层海温资料和CCSM3模式的1870—1999年130a模拟试验的结果,分析了北太平洋年代际变化(PDO)的三维空间结构和时间演变特征。结果表明,CCSM3模式较好的模拟了北太平洋年代际变化的主要特征,对再分析资料和模式结果的分析都表明从北太平洋表层至次表层的中层,年代际变化是非常显著的,PDO不仅仅局限于表层海洋,而是一个深厚的系统。北太平洋年代际振荡在海洋次表层存在一个信号传播通道,PDO的信号是沿着副热带海洋环流在海洋次表层顺时针传播的,从北太平洋东部沿西南方向传播到热带西太平洋,随后向北到黑潮-亲潮延伸区附近,最后向东传播至北太平洋中部,完成一次位相的转换。在信号传播的过程中深度逐步加深,最后在北太平洋中部达到最深。

Using reanalysis ocean subsurface data and 130 a（1870—1999） results of CCSM3 model of NCAR,this study examines the 3-D spatial structures and the temporal evolution of Pacific Decadal Oscillation（PDO）.The results indicate the model simulates well many features of the observed North Pacific variability.Both the reanalysis data and the models results show that the pattern of PDO is not prescribed in the ocean surface,but exists in the whole top North Pacific Ocean from surface to subsurface.There is a passage of PDO signal propagation in subsurface of the North Pacific Ocean which exhibits a clockwise rotation in an association with the subtropical gyre： form the eastern North Pacific propagates west-southward to the tropical western Pacific,and then northward to the Kuroshio/Oyashio extension（KOE） region,then eastward reaching the middle of North Pacific at last,which complete a phase-changing.However,the propagation of PDO signal is not in the same depth,but is deepening gradually,and the depth is deepest when the signal reaches the middle of North Pacific at last.