An investigation of the El Niño‐Southern Oscillation cycle With statistical models: 1. Predictor field characteristics
An investigation of the El Niño‐Southern Oscillation cycle With statistical models: 1. Predictor field characteristics
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DOI：
10.1029/jc092ic13p14251
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发表时间：
1987-12
影响因子：
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通讯作者：
N. Graham;J. Michaelsen;T. Barnett
中科院分区：
文献类型：
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作者：
N. Graham;J. Michaelsen;T. Barnett
利用印度太平洋信风场和近全球海平面压力场，建立了两套预测赤道太平洋海面温度（SSTs）的线性模型。该模型采用扩展经验正交函数（EEOFs）和典型相关分析（CCA）相结合的方法构建。我们的结果很有意义，因为它们显示了厄尔尼诺-南方涛动周期中SLP和风场的主要演化模式，以及关于赤道海温的预测问题。本文讨论了上面的第一个问题，并描述了一些统计组合，这些统计组合代表了多年来预测字段中特征的发展。EEOF分析的结果清楚地表明，近全球SLP和信风场的异常传播缓慢。CCA分析强调了两个场的共同演化，表明两者之间存在很强的耦合，并将异常特征描述为首先出现在东印度洋的辐散和辐合迁移中心。这些特征缓慢地向东传播，扩展到西太平洋时增强，穿过中央大洋时减弱，然后在东太平洋上空再次增强。随着再放大的发生，印太地区出现了新的对立异常。对预测数据集的描述和所使用的统计技术的细节也可以在本文中找到。海温数据、模型验证技术和预测模型结果在一篇配套论文（Graham et al.，本期）中提出。
We have developed two sets of linear models for predicting equatorial Pacific sea surface temperatures (SSTs) from the Indo-Pacific trade wind field and the near-global sea level pressure (SLP) field. The models were constructed using a combination of extended empirical orthogonal functions (EEOFs) and canonical correlation analysis (CCA), a new approach in geophysical modeling. Our results are of interest both as they show the dominant modes of evolution in the SLP and wind fields through the El Nino-Southern Oscillation cycle and with respect to the problem of predicting equatorial SSTs. This paper deals with the first issue above and describes some statistical composites that typify the development of features in the predictor fields over periods of years. The results of the EEOF analyses clearly show slowly propagating anomalies in both the near-global SLP and trade wind fields. The CCA analysis, which highlights the co-evolution of the two fields, suggests a strong coupling between the two and depicts the anomalous features as migrating centers of divergence and convergence that first appear over the eastern Indian Ocean. These features propagate slowly eastward, amplify as they expand into the western Pacific, decline as they cross the central ocean, then reamplify over the eastern Pacific. As reamplification takes place, new opposing anomalies appear in the Indo-Pacific. Descriptions of the predictor data sets and details of the statistical techniques used may also be found in this paper. The SST data, model validation techniques, and forecast model results are presented in a companion paper (Graham et al., this issue).