Decadal Oscillations in a Simple Coupled Model
Decadal Oscillations in a Simple Coupled Model
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简单耦合模型中的年代际振荡
DOI：
10.1175/1520-0442(1998)011
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
E. Maier‐Reimer
中科院分区：
文献类型：
--
作者：
M. Münnich;M. Latif;S. Venzke;E. Maier‐Reimer
为了研究可能导致北太平洋年代际振荡的动力学，发展了一个简单的耦合模式。海洋是基于斜压行星波的线性势涡方程。大气被简化为对温跃层深度异常的非局地风响应。风应力具有空间固定结构，其振幅取决于某一位置或某一预定指数区域的温跃层扰动。
To study the dynamics that may lead to decadal oscillations in the North Pacific a simple coupled model is developed. The ocean is based on the linear, potential vorticity equation for baroclinic planetary waves. The atmosphere is reduced to a nonlocal wind response to thermocline depth anomalies. The wind stress has a spatially fixed structure and its amplitude depends on the thermocline perturbation at one location or in a predefined index region.
Such a simple coupled model produces decadal oscillations for suitable parameter choices. For realistic wind stress patterns, the patterns of oceanic variability are similar to those observed. It is determined by the speed of long Rossby waves at the coupling latitude. The period of the oscillation is rather insensitive to the coupling strength and amounts to approximately twice the time the Rossby wave needs to travel from the center of the wind stress curl anomaly to the coupling location.
A stochastic component to the atmospheric forcing is incorporated by white noise added to the feedback. With such a forcing, typical oceanic spectra become red with a broad peak at decadal timescales superimposed.