Recalculation of surface slopes as forcing for numerical water column models of tidal flow

A new method for forcing numerical one-dimensional (1D) water column models of turbulent tidal flow is presented. It needs as an input time series of water depth and velocity at one point in the water column. These time serie s are here interpreted as indirect measurements of the surface slope. The m ethod is based on an operator splitting technique as discretization in time in order to guarantee exact reproduction of the input data. For simple two -dimensional (2D) flow in the xz plane, a parametrization of horizontal adv ection is given which slightly improves the results. This new method is val idated against the performance of a three-dimensional (3D) estuarine model from which forcing data for the 1D model have been extracted. The advantage of this method in relation to the classical method (prescription of surfac e slopes) is demonstrated. As a demonstration of its potential, the method is finally applied to turbulent tidal flow in the Eastern Scheldt, The Neth erlands. (C) 1999 Elsevier Science Inc. All rights reserved.