Application of LICOM to the numerical study of the water exchangebetween the South China Sea and its adjacent oceans

On the basis of 900-year integration of a global ocean circulation model-LICOM driven by ECMWF reanalysis wind data with uniform 0.5°-grids,a quantitative estimate of the annual and monthly mean water exchange of the South China Sea(SCS) with its adjacent oceans through 5 straits is obtained.Among them,the annual transport is the largest in the Luzon Strait,then in the Taiwan Strait,and then in the Sunda Shelf,in the Balabac Strait and in the Mindoro Strait in turn,the largest monthly transport variation appears in the Luzon Strait and Sunda shelf.It is shown that the mass transport through the Taiwan Strait is affected by monsoon,while the transport through the Luzon Strait may be associated with the bifurcation position of the North Equatorial Current off the east Philippines shore;the transports in the Luzon Strait and Sunda Shelf are out of phase in direction but well correlated in magnitude.The annual and monthly mean heat and salinity exchange of the SCS through the straits are also calculated and shown to be in phase with the mass transport.The Kuroshio water carries about 0.43 PW heat transport and 151.33 kt/s salinity transport into the SCS,while most of them is carried out of the SCS through the Taiwan Strait and Sunda Shelf annually.The further model integration based on the 900-year integration for another 44 a from 1958 to 2001 driven by real wind data(ERA40 data) shows that the monthly mean mass transport via these straits varies annually with a large variation range,which may be associated with the seasonal and interannual variations in the current field and sea surface height in the SCS.The mean mass transport through the Taiwan Strait,Luzon Strait,Mindoro Strait,Balabac Strait and Sunda Shelf is 2.012×10⁶,-4.063×10⁶,-0.124×10⁶,-0.083×10⁶ and 2.258×10⁶ m³/s,respectively.