Averaging Principle for Quasi-Geostrophic Motions under Rapidly   Oscillating Forcing
  In this paper, the averaging principle for quasi-geostrophic motions with rapidly oscillating forcing is proved, both on finite but large time intervals and on the entire time axis. This includes comparison estimate, stability estimate, and convergence result between quasi-geostrophic motions and its averaged motions. Furthermore, the existence of almost periodic quasi-geostrophic motions and attractor convergence are also investigated. 
Hongjun Gao and Jinqiao Duan