The sea level in the southern South China Sea (Sunda Shelf) region is mainly determined by the tides and the monsoon/local wind systems. In order to facilitate early warning of any extreme sea level events, a regional storm surge forecast system is operational in TMSI, NUS. The Mercator Ocean forecast / reanalysis product has been used as initial and lateral boundary conditions for the TMSI storm surge forecast model. The Regional Ocean Model System (ROMS) configured for the Eastern Indian Ocean-South China Sea-Western Pacific domain is used in the forecast system. The surface boundary condition for the model is derived from NCEP-GFS (National Centers for Environmental Prediction– Global Forecast System; NOAA).
On the first figure : Storm Surge forecast using ROMS. Low sea level in the southern South China Sea due to the strong southwest monsoon wind is seen as blue shade.
The second one shows the timeseries plot of storm surge forecast at Singapore, with comparisons with sea level observations from a Singapore tide gauge. The storm surge forecasts are generally satisfactory as it shows reasonable agreement with the observations. Aside from Mercator Ocean products, other forecast products may also used, for example, HYCOM.
Initial and lateral boundary conditions for TMSI