Approximation of ensemble members in ocean wave prediction

An efficient method for generating members in a ocean wave ensemble prediction system is proposed. A linearization of the wave model WAM is used to obtain approximations of the ensemble members. This procedure was originally introduced in a dynamical assimilation scheme where Green's functions play a central role. The evaluation of member approximations can be carried out in a fraction of the time required by the full model integration. This aspect of the method suggests a way of increasing the ensemble size as well as refining the model resolution without increasing Computational costs.