Numerical research on evolvement of submarine sand waves in the Northern South China Sea

Abstract

Submarine sand waves, vital to seabed stability, are an important consideration for oceanic engineering projects such as oil pipe lines and submarine cables. The properties of surface sediment and the evolvement of submarine sand waves in a specified area in the South China Sea are studied using both a hydrological model and field observational data. The bottom flow field data between 2010 and 2011 in the study area are simulated by the Regional Ocean Model System (ROMS). The migration of submarine sand waves is calculated using Rubin’s formula along with typhoon data and bottom flow field data, which allows for the analysis of sand wave response under the influence of typhoons. The migration direction calculated by Rubin’s formula and bottom flow are very similar to collected data. The migration distance of different positions is between 0.0 m and 21.8 m, which reciprocates cumulatively. This shows that Rubin’s formula can predict the progress of submarine sand waves with the bottom flow simulated by ROMS. The migration distances of 2 sites in the study area are 2.0 m and 2.9 m during the typhoon “Fanapi”. The proportion of the calculated migration distance by the typhoon is 9.17% and 26.36% of the annual migration distance, respectively, which proves that the typhoon can make a significant impact on submarine sand waves.