A simple ocean circulation model is used to study the multicentennial variability of the Atlantic meridional overturning circulation (AMOC). Firstly, a latitude-averaged 2-D ocean circulation model is derived, and the control equation and key parameters for AMOC are established. Then, through numerical methods, a reasonable mean climate of AMOC is simulated under appropriate boundary conditions and external forcings. To excite the multicentennial variability of AMOC, a long-term integration is carried out by adding a random salinity flux forcing to the subpolar surface layer of the Northern Hemisphere. Power spectrum analysis results show that AMOC can exhibit oscillations with a period of about 260 years. The first spatial mode obtained from the EOF decomposition of AMOC exhibits signals primarily in the deeper ocean basins, indicating that the multicentennial variability may be closely linked to changes in the deeper ocean. The relationship between the oscillation period and the volume of the ocean basin as well as the strength of AMOC is also explored. Larger basin volumes are associated with longer oscillation periods, while stronger AMOC correlates with shorter periods.

利用简单海洋环流模式, 对大西洋经向翻转流(AMOC)的多百年际振荡进行模拟研究。首先推导纬向平均的二维海洋环流模式, 得到AMOC的控制方程及关键参数。然后利用数值方法, 使用混合边界条件, 在合适的边界条件和强迫场条件下模拟合理的AMOC气候态。通过向北半球副极地表层添加盐度通量随机强迫, 进行长时间积分, 激发AMOC的多百年际变率。功率谱分析结果表明, AMOC可以展现约260年的周期性振荡, 对AMOC进行EOF分解得到的主模态主要信号位于较深的海盆, 表明多百年际变率可能与较深层海洋的变动联系紧密。最后探究振荡周期与海盆体积及AMOC强度的关系, 海盆体积越大, 振荡周期越长; AMOC越强, 振荡周期越短。