4D-Var data assimilation system for a coupled physical-biological model

A 3-compartment model of phytoplankton growth dynamics has been coupled wit h a primitive-equation circulation model to better understand and quantify physical and biological processes in the Adriatic Sea. This paper presents the development and application of a data assimilation procedure based on o ptimal control theory. The aim of the procedure is to identify a set of mod el coefficient values that ensures the best fit between data and model resu lts by minimizing a function that measures model and data discrepancies. In this sense, twin experiments have been successfully implemented in order t o have a better estimation of biological model parameters and biological in itial conditions.