Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports

Abstract

A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea.

Tides and Their Dynamics over the Sunda Shelf of the Southern South China Sea

“…The bathymetry of the outer and inner domains is based on ETOPO2 (refer to: http://www.ngdc.noaa.gov ), which is derived from the depth soundings and satellite gravity observations [ 21 ]. However, the bathymetry is smoothed to reduce the pressure gradient error to an acceptable level by using the relative bathymetric gradient ( r = ∇h/h ) to be 0.2 [ 6 – 7 , 11 ]. The outer domain has a horizontal resolution of 0.25°×0.25° which is approximately 25 km and is vertically separated into 30 S -levels following the bathymetry but with a minimum depth (hmin) setting of 5 m at the shore.…”

“…It is connected to the Java Sea through the Sunda Shelf in the south. Monsoonal winds have great influence on the sea circulation in the SSCS [ 1 – 11 ]. Furthermore, sea surface and seabed also have different significant impacts on wind-induced circulations as well as on the distribution, propagation and dissipation of tidal energy flux [ 12 ] with complicated tidal dynamics, especially at the bottom [ 13 – 15 ].…”

Phylogeography of the reticulated python (Malayopython reticulatus ssp.): Conservation implications for the worlds’ most traded snake species

“…Active marine dispersal from Java to Sumatra and vice versa could be facilitated by the circulation of sea surface currents triggered by monsoon winds, i.e. December–February south-eastern currents from Sumatra to Java, then June–August north-western currents from Java to Sumatra [ 90 , 91 ]. The species may therefore have crossed marine barriers as has been reported for the estuarine crocodile ( Crocodylus porosus ) [ 92 ], however, it is also noted that the ‘ human agency on boats is highly significant’ with regard to the dispersal of terrestrial vertebrates in the Sunda Strait [ 93 ].…”

Fuzzy Optimized MFAC Based on ADRC in AUV Heading Control

“…The temperature, salinity, and density have a little influence on the motion performance of AUV and can be neglected, thus sea current interference is the only interference we need to consider. Suppose that the current is parallel to the water level of the fixed coordinate system, and the current is constant [27]. In the current circumstances, the relative velocity as shown in (7)- (9).…”