ENSO components of the Atlantic multidecadal oscillation and their relation to North Atlantic interannual coastal sea level anomalies
ENSO components of the Atlantic multidecadal oscillation and their relation to North Atlantic interannual coastal sea level anomalies
复制标题
大西洋数十年振荡的 ENSO 分量及其与北大西洋年际沿海海平面异常的关系
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
G. Dusek
中科院分区：
文献类型：
--
作者：
Joseph Park;G. Dusek
抽象的。众所周知，厄尔尼诺南方涛动(ENSO)和大西洋十年振荡(AMO)会影响美国东海岸的沿海水位。通过识别从多变量ENSO指数(MEI)到AMO指数(AMO)的相干贡献的经验正交函数(EOFs)，我们描述了ENSO在非平滑的AMO指数中的表达，以及这些指数与墨西哥湾和北大西洋西部6个站的海平面年际异常之间的相关性关系。在ENSO波段内(2-7年)，MEI对非平滑的淘大环流变率的总贡献率为79%。相关分析表明，MEI使ENSO信号的表达提前了6个月，这与大气桥梁的机制是一致的。在ENSO波段内，非平滑的厦门站与海平面异常之间的耦合基本上都是ENSO在厦门站的表现。在较长的周期内，我们在三个南部站(基韦斯特、彭萨科拉、查尔斯顿)发现了与厦门岛有关的海平面异常的年代际分量，但在北部站(巴尔的摩、波士顿、波特兰)没有发现海平面异常的年代际分量，其相干性值在20%到50%之间。MEI与沿海海平面异常的相关性具有不同的结构，总体上弱于ENSO表现的厦门影响，这表明与基于厦门地区ENSO表达的遥相关相比，不同的物理机制对海平面异常的影响是由于直接的ENSO遥相关。预计将这一分析应用于极端的海平面异常将揭示更多的影响。
Abstract. The El Nino Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO) are known to influence coastal water levels along the East Coast of the United States. By identifying empirical orthogonal functions (EOFs), which coherently contribute from the Multivariate ENSO Index (MEI) to the AMO index (AMOI), we characterize both the expression of ENSO in the unsmoothed AMOI, and coherent relationships between these indices and interannual sea level anomalies at six stations in the Gulf of Mexico and western North Atlantic. Within the ENSO band (2–7 yr periods) the total contribution of MEI to unsmoothed AMOI variability is 79%. Cross correlation suggests that the MEI leads expression of the ENSO signature in the AMOI by six months, consistent with the mechanism of an atmospheric bridge. Within the ENSO band, essentially all of the coupling between the unsmoothed AMOI and sea level anomalies is the result of ENSO expression in the AMOI. At longer periods we find decadal components of sea level anomalies linked to the AMOI at three southern stations (Key West, Pensacola, Charleston), but not at the northern stations (Baltimore, Boston, Portland), with values of coherence ranging from 20 to 50%. The coherence of MEI to coastal sea level anomalies has a different structure and is generally weaker than that of the ENSO expressed AMOI influence, suggesting distinct physical mechanisms are influencing sea level anomalies due to a direct ENSO teleconnection when compared to teleconnections based on ENSO expression in the AMOI. It is expected that applying this analysis to extremes of sea level anomalies will reveal additional influences.