Initialization and Data Assimilation in Models of the Indian Ocean

Abstract

Sch. Mathe., Univ. New South Wales, Kensington, N.S.W., Australia ISSN 0022-3670 J (Journal-Article) M (Marine) Numerical experiments have been conducted to investigate the effect of updating models of the Indian Ocean using simulated temperature (mass) and velocity data. Two models are used: a linear reduced gravity model with one active layer, and a nonlinear 12-level general circulation model (GCM). In both cases an "identical twin" approach is adopted, in which the same model is used to generate the "observed" data in a "truth run", as is used in the assimilation run. Temperature data is found to be better than velocity data for initializing both models. However, further experiments with the layer model showed that increasing the model diffusion and decreasing the eddy viscosity results in velocity data being better for initializing. These results are ascribed to the energy distribution, with the proportion of kinetic energy bein...