Influence of MeteOcean processes on MSYM sea level predictions in the Malacca Straits

Abstract

The South China Sea region, and particularly the Malacca and Singapore Straits, are known by the complex tidal dynamics, which is influenced by the tidal propagation from Pacific and Indian Oceans. In spite of the dynamic complexity, the region is very relevant economically, especially concerning the growing oil drilling activities. To give support to accidental oil spill prevention and response, an operational oil spill forecast system was developed for the Strait of Malacca. The hydrodynamic system validation revealed good results, in general. However, besides all the modeling efforts, some discrepancies between observed and predicted sea levels were identified, mainly during neap tide and for specific tide-gauges. Therefore, the main aim of this study consists in researching the origin of these discrepancies by comparing predictions with available data and exploring their relation with the MeteOcean processes of the region. Initially sea level data for eight tide gauges was explored to get a general overview of the local tidal dynamics, and then the model performance for astronomic tide was assessed. Analysis of meteorological tides was also performed for three tide-gauges located in the Singapore and Malacca Strait, which are under the influence of the northeast or southwest monsoons. The results show that the differences between the observed and predicted sea levels in Singapore Strait are usually due to discrepancies in the meteorological tide induced by the surface wind stress acting over the Taiwan-Singapore axis, while in the Malacca Strait are mainly related with model limitations in reproducing the astronomical tide.