A reduced-order model for the regeneration of surface currents in Gorgan Bay, Iran

Abstract

Abstract This study developed a hydrodynamic reduced-order model (ROM) to regenerate surface currents in Gorgan Bay, Iran. The developed ROM was based on linking a three-dimensional hydrodynamic model, MIKE3-FM, with a data reduction technique, proper orthogonal decomposition (POD). The MIKE3-FM model was first run to simulate surface currents in the bay under a real wind scenario for two years starting July 1, 2010. Thereafter, time and space steps of 6 hours and 500 m, respectively, were chosen to capture 2,920 snapshots of the simulated surface currents using the MIKE3-FM model on 1,937 grids in the bay. The snapshots were then used as input for the POD model to develop the ROM. By applying the POD on the snapshots, necessary spatial and temporal components of surface currents used to develop the ROM were calculated. Having spatial and temporal terms, two ROMs for regeneration of surface currents U and V in two directions x and y, respectively, were developed. Analysis of ROM results revealed they accurately regenerated surface currents using only the first ten modes (among 2,920 modes). Comparison of MIKE3-FM and ROMs developed by the first ten modes revealed there were only negligible differences between their results when they simulated and regenerated, respectively, U and V, in the bay.