A Two-Level Finite Element Discretization of the Streamfunction   Formulation of the Stationary Quasi-Geostrophic Equations of the Ocean
  In this paper we proposed a two-level finite element discretization of the nonlinear stationary quasi-geostrophic equations, which model the wind driven large scale ocean circulation. Optimal error estimates for the two-level finite element discretization were derived. Numerical experiments for the two-level algorithm with the Argyris finite element were also carried out. The numerical results verified the theoretical error estimates and showed that, for the appropriate scaling between the coarse and fine mesh sizes, the two-level algorithm significantly decreases the computational time of the standard one-level algorithm. 
Erich L Foster and Traian Iliescu and David Wells
math.NA