Error evolution in the dynamics of an ocean general circulation model

The problem of error propagation is considered for spatially uncorrelated e rrors of the barotropic stream function in an oceanic general circulation m odel (OGCM). Such errors typically occur when altimetric data from satellit es are assimilated into ocean models. It is shown that the error decays at first due to the dissipation of the smallest scales in the error field. The error then grows exponentially before it saturates at the value correspond ing to the difference between independent realizations. A simple analytic f ormula for the error behavior is derived; it matches the numerical results documented for the present primitive-equation ocean model, and other models in the literature. (C) 2000 Elsevier Science B.V. All rights reserved.