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 ?. We prove the existence of the uniform global attractor A^?. Furthermore, using the method of 11] in the case of the two-dimensional Navier-Stokes systems, we study the convergence of A^? as ? goes to zero.