Evidence of nonlinear dynamics in the eastward shift of the NAO
Evidence of nonlinear dynamics in the eastward shift of the NAO
复制标题
DOI：
10.1029/2002gl015585
复制
发表时间：
2003-01
影响因子：
5.2
通讯作者：
K. Peterson;Jian Lu;R. Greatbatch
中科院分区：
文献类型：
--
作者：
K. Peterson;Jian Lu;R. Greatbatch
Hilmer和Jung [2000]已经确定了与1980年左右发生的北大西洋涛动（NAO）年际变化相关的海平面气压（SLP）模式的东移。我们调查的性质东移使用原始方程，干大气模式驱动的非绝热强迫诊断观测。模拟结果表明，NAO的空间分布与NAO指数呈非线性关系，高（低）NAO指数时，NAO的空间分布向东（西）移动。一般协议之间的模型和观察。我们认为，Hilmer和Jung [2000]指出的东移是世纪最后几十年NAO指数上升趋势的结果。
Hilmer and Jung [2000] have identified an eastward shift in the sea level pressure (SLP) pattern associated with interannual variability of the North Atlantic Oscillation (NAO) that took place around 1980. We investigate the nature of the eastward shift using a primitive equation, dry atmospheric model driven by diabatic forcing diagnosed from observations. The model results reveal the nonlinear dependence of the spatial pattern of the NAO on the NAO index, the pattern being shifted to the east (west) for high (low) NAO index. General agreement is found between the model and observations. We suggest that the eastward shift noted by Hilmer and Jung [2000] is a consequence of the trend towards higher NAO index during the last several decades of the 20th century.