On the Warm Water Volume and Its Changing Relationship with ENSO
On the Warm Water Volume and Its Changing Relationship with ENSO
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DOI：
10.1175/jpo-d-13-062.1
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发表时间：
2014-04
影响因子：
3.5
通讯作者：
L. Bunge;A. J. Clarke
中科院分区：
文献类型：
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作者：
L. Bunge;A. J. Clarke
摘要：自1980年以来，赤道太平洋20°C等温线深度的年际变化主要由两种经验正交函数（EOF）模态主导：“倾斜”模态，在赤道东太平洋和西太平洋具有相反的符号，与纬向风强迫和厄尔尼诺-南方涛动（ENSO）指数同相，以及跨太平洋的单一符号的第二种EOF模态。由于赤道东太平洋和西太平洋的倾斜模态具有相反的符号，而第二个EOF模态具有同一个符号，因此第二模态与温水体积（WWV）相关，温水体积定义为从5°S到5°N、120°E到80°W的20°C等温线以上的水体积。过去的研究表明，WWV 领先倾斜模式约 2-3 个季节，使其成为 ENSO 的预测因子。但 1998 年之后，领先优势有所下降，基于 WWV 的 ENSO 预测也失败了。作者在 1955 年构建了基于海平面的 WWV 代理，在 1973 年之前也表现出较小的领先优势。自 1980 年以来的数据分析表明，...
AbstractThe interannual, equatorial Pacific, 20°C isotherm depth variability since 1980 is dominated by two empirical orthogonal function (EOF) modes: the “tilt” mode, having opposite signs in the eastern and western equatorial Pacific and in phase with zonal wind forcing and El Nino–Southern Oscillation (ENSO) indices, and a second EOF mode of one sign across the Pacific. Because the tilt mode is of opposite sign in the eastern and western equatorial Pacific while the second EOF mode is of one sign, the second mode has been associated with the warm water volume (WWV), defined as the volume of water above the 20°C isotherm from 5°S to 5°N, 120°E to 80°W. Past work suggested that the WWV led the tilt mode by about 2–3 seasons, making it an ENSO predictor. But after 1998 the lead has decreased and WWV-based predictions of ENSO have failed. The authors constructed a sea level–based WWV proxy back to 1955, and before 1973 it also exhibited a smaller lead. Analysis of data since 1980 showed that the decreased ...