Numerical Prediction and Correction of Tidal Forcing for Kaohsiung Second Harbor Using ROMS

Ho-Shuenn Huang
Institute of Ocean Engineering and Technology,
National Kaohsiung Marine University, Taiwan
E-Mail address: hoshuenn@mail.nkmu.edu.tw

Abstract

This study attempts to investigate and then predict the ocean dynamics neighboring Kaohsiung Second Harbor in Taiwan by utilizing ROMS. Effects of tidal forcing and current are presently involved in numerical simulations while comparing with the measured sea level data from the NKMU buoy and/or other units.

The terrain of the computational domain over the Kaohsiung Second Harbor is input according to the given geographic coordinates (longitude and latitude) to form the bathymetry file. Then, SEAGRID or EASYGRID generate the grids which are nearly orthogonal. There are in total 139 (east, west) × 139 (south, north) × 20 (depth) grid resolutions. During the numerical simulations, a time step of 2 sec is selected for securing the stable CFL condition. Tidal forcing is specified on the southern boundary, in which case the free-surface Chapman condition and 2D momentum Flather condition are utilized. Open boundary conditions with 3D momentum radiation conditions are also imposed.

It was found that the proposed numerical models were able to fairly predict the sea level of the tidal forcing and current nearby Kaohsiung Second Harbor where there existed irregular changeovers of the diurnal and semi-diurnal tides.