本文对北半球大湖中普遍存在的大规模反时针环流的形成,提出了一种物理解释,认为大气在经过湖体时的地转适应过程产生了一个有利于这种环流形成的附加风场。这种环流的强度在一年四季中是变化的,夏季最强,冬季最弱。在此理论的基础上建立了一个三维非线性水动力学数学模型。数值试验表明,风场的有旋性对这种环流的形成起了决定性的作用。计算得到的环流形态基本上与实测结果相吻合。 In this paper, we propose a physical explanation for the formation of a large-scale anticlockwise circulation in the Great Northern Hemisphere. It is believed that the geostrophic adaptation process in the lakes produces an additional wind field conducive to this circulation. The intensity of this circulation varies throughout the year, with strongest in summer and weakest in winter. Based on this theory, a three-dimensional nonlinear hydrodynamic mathematical model is established. Numerical experiments show that the curvature of the wind field plays a decisive role in the formation of this circulation. The calculated shape of the circulation basically coincides with the measured results.