A model of the formation and development of ocean shear wave

From quasi-geostrophic vorticity equation,we simulate the formation of ocean shear wave in western boundary strong current area with the pseudospectral method,and idealize the initial velocity into hyperbolic tangent velocity profile,with the unsteady little perturbation developed by means of getting energy from mean motion.The change of isovorticity shows two vortexes merging or splitting between them.The evolving process of material lines reflects cold water's invading and warm water's turning,which is agreeable to satellite photograph.Vonlinear effect makes a new energy distribution in all kinds of motion scale.One important phenomenon is that Reynolds stress will change its sign when the perturbation amplitude is large enough.