The spectral wave model, WAM, adapted for applications with high spatial resolution

New features have been added and several necessary changes have been made t o the standard WAM-cycle4 (WAMC4) model code for it to run efficiently when applied to shallow water regions. The restriction of having a source term integration time step smaller than or equal to the propagation time step wa s relaxed, considerably reducing the computational time needed. An addition al reduction in computing time and an increase in accuracy were obtained by introducing a split-frequency time step. There is now a choice of using th e octant or quadrant coordinate system for the propagation of the wave ener gy. The source term integration and, more particularly, the use of a limite r on the energy growth, were studied. For the evaluation of the energy deca y in shallow water areas, different bottom friction formulations and an exp ression for the energy dissipation due to depth-induced wave breaking were added to the code. The procedure to make nested runs was changed in order t o save data storage space and time spent on input/output (I/O) operations. Several other changes were done in order to improve the accuracy in high-re solution applications. A number of simple or idealised example applications are included to illustrate some of these enhancements. (C) 2000 Elsevier S cience B.V. All rights reserved.