Approaches to Data Assimilation within GODAE

Abstract – The main purpose of this paper is to review some key issues and challenges for ocean data assimilation in the perspective of GODAE. This includes the “high-resolution challenge ” and simultaneous trend towards the use of dynamically-consistent methods, the problem of modelling multivariate error covariances in “simple ” OI-type schemes, verification of physical consistency, internal consistency checks via the calculation of residual (analysis minus observation) statistics, further extraction of information by adaptive algorithms, effect of assimilation on unobserved variables, forecasting skill, error dynamics in “advanced” schemes, as well as considerations on the performance of the observational network. GODAE is expected to boost the inter-comparison exercises between assimilating systems, as well as to provide a forum to discuss the areas where progress is needed in the next years