Nonlinear dynamics in geosciences
Nonlinear dynamics in geosciences
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DOI：
10.1007/978-0-387-34918-3
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
A. Tsonis;J. Elsner
中科院分区：
文献类型：
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作者：
A. Tsonis;J. Elsner
我们提出了过去135年来ENSO与北半球冰情之间动态联系的观测证据。利用小波变换（WT），我们从时间序列中分离出具有统计意义的分量，并在2.2、3.5、5.7和13.9年的周期内证明了北半球冰况与北极涛动和南方涛动指数（AO和SOI）之间存在显著的协方差和一致的相位差异。为了研究弱相互作用振荡系统的相动力学，我们采用了平均互信息和平均相相干方法。不同频率信号的相位关系表明，2.2-5.7年和13.9年信号的分布存在多种机制。早三个月在热带太平洋产生的2.2- 5.7年的信号通过平流层传播，而北极涛动（AO）介导了信号的传播。相比之下，13.9年的信号从西太平洋向东传播赤道耦合海浪，然后沿美洲西部边缘快速边界波到达两极地区，到达北极时的相位差约为1.8-2.1年。
We present observational evidence of the dynamic linkages between ENSO and Northern Hemisphere (NH) ice conditions over the past 135 years. Using Wavelet Transform (WT) we separate statistically significant components from time series and demonstrate significant co-variance and consistent phase differences between NH ice conditions and the Arctic Oscillation and Southern Oscillation indices (AO and SOI) at 2.2, 3.5, 5.7 and 13.9 year periods. To study the phase dynamics of weakly interacting oscillating systems we apply average mutual information and mean phase coherence methods. Phase relationships for the different frequency signals suggest that there are several mechanisms for distribution of the 2.2-5.7 year and the 13.9 year signals. The 2.2- 5.7 year signals, generated about three months earlier in the tropical Pacific Ocean, are transmitted via the stratosphere, and the Arctic Oscillation (AO) mediating propagation of the signals. In contrast the 13.9 year signal propagates from the western Pacific as eastward propagating equatorial coupled ocean waves, and then fast boundary waves along the western margins of the Americas to reach both polar regions, and has a phase difference of about 1.8-2.1 years by the time it reaches the Arctic.