倾斜西海岸线的正压海洋对中纬西风的响应

Barotropic ocean model with tilting western coast forced by mid-latitude western wind

用超松弛迭代法数值求解带有非线性平流项的正压准平衡海洋模型,以讨论在东北—西南向的倾斜西海岸线下,海洋流场对中纬西风强迫的响应。当存在该倾斜时,海洋响应中关于β通道中心轴线的对称性遭破坏。倾斜度越大,西海岸处β通道中流函数零线与西海岸线的夹角越小,且其位置也向北偏移得越多;倾斜度固定时,地面西风急流形式的风场分布得越宽阔,上述偏移越明显。非线性下存在解对参数很敏感和迭代不收敛的情况,但在取典型参数时非线性与线性两者的计算结果几乎相同。考虑西海岸线倾斜后的结果较取正南北向的结果更接近于真实,这表明该倾斜的影响是重要和不可忽视的。

A partial differential equation with nonlinear term was established from the barotropic quasi-equilibrium ocean model with nonlinear advection term,and its solutions were obtained by over-relaxation iteration method.This equation was used to discuss the oceanic flow with tilting western coast how to correspond to the mid-latitude westerly anomalies.The symmetric structure about the β channel center line of the corresponding flow will be destroyed when the western coast is tilting,and the angle between the zero line of the flow function in the β channel and the western coast will be bigger when the inclination is more obvious,and the northern migration of the zero line will be more obvious.When the angle of inclination is fixed,the migration will be more obvious with more broad near-surface western wind.The problems existing in the solutions of the nonlinear condition are that the solutions are sensitive to parameters and the iteration can not converge.However,the computing results of the nonlinear condition are almost the same as those of the linear condition when the paremeters are classical.After considering the inclination of the western coast,the computing results are closer to the reality,suggesting that the inclination is very important and can not be ignored.