Optimal determination of nudging coefficients using the adjoint equations

In this study, a general computational procedure is developed to determine the size and distribution of any internal model parameter. The procedure is then applied to a one-dimensional shallow-water model in the context of analysis-nudging four-dimensional data assimilation (FDDA): the weighting coefficients used by the Newtonian nudging technique are determined such that the model error during the assimilation period is optimally reduced subject to some constraints. The sensitivity of these nudging coefficients to the optimal objectives and constraints is investigated using this simple grid-point model in an Observing Systems Simulation Experiments (OSSE) mode. -from Authors