Modelling Sea Level Anomalies in Malacca Strait.

Serene Hui Xin Tay, Alamsyah Kurniawan, Seng Keat Ooi, Vladan Babovic

Wednesday 1 july 2015

12:00 - 12:15h at Amazon (level 1)

Themes: (T) Water engineering, (ST) River and coastal engineering

Parallel session: 9C. Coastal engineering

Geographically located between the Andaman Sea and the South China Sea, the water level in the Malacca Strait is indirectly driven by tide and other hydrodynamic components from the two oceans: Indian Ocean and Pacific Ocean. By extracting tidal signal from long term water level observation, the residual or sea level anomalies (SLA) in the Malacca Strait amount to more than +/- 30 cm. Earlier numerical studies of using both tidal and meteorological forcing have failed to represent the SLA well in the Malacca Strait, and suggested that the SLA is induced by large scale oceanographic effect beyond the strait, more likely from the Indian Ocean. The present paper will attempt to enhance the existing tide and wind modelling approach by applying water level correction on the model’s open boundary to improve the SLA representation in the strait. There are two options to derive this open boundary water level correction: (1) SLA derived from satellite altimetry at the boundary location, and (2) offline nesting in a large scale reduced depth model covering the entire Indian Ocean driven by wind and atmospheric pressure. This paper will assess the improvement of SLA representation in the Malacca Strait using different model forcing, and describe the seasonal volume flux through the strait induced by tidal and non-tidal components. The results of this study would serve as the basis of a hydrodynamic modelling framework for delivering accurate hindcast and forecast predictions in the Malacca Strait.