Averaging of the planetary 3D geostrophic equations with oscillating external forces

In this article, we consider a non-autonomous three-dimensional planetary geostrophic model of the ocean with a singularly oscillating external force depending on a small parameter ϵ  . We prove the existence of the uniform global attractor AϵAϵ. Furthermore, using the method of [11] in the case of the two-dimensional Navier–Stokes systems, we study the convergence of AϵAϵ as ϵ goes to zero.