Results and Discussion
Responses of the Marine Environment in the SCS and CS to Climate Change
Sea Surface Temperature (SST)
The IPCC AR5 concluded that SST in the Pacific Ocean has increased by 0.31 °C for 1950-2009 due to global climate change (Hoegh-Guldberg et al. 2014). In this study, based on the annual mean HadISST and SODA analysis, long-term linear changes of SST in the SCS and the CS for 1958-2014 were analyzed using the linear fitting method. The results indicate that the SST in most of the SCS, especially in its central and northeastern areas, has increased by 0.8 - 1.8 ± 0.11 °C (95% confidence interval) during 1958-2014, at a rate of 0.14-0.31 °C decade-1 (Fig. 10.1a). Over the same period, the SST in the CS has increased by 0.4 - 0.8 ± 0.11 °C (95% confidence interval), at a rate of 0.07-0.14 °C decade-1 (Fig. 10.1a). The figure also shows that surface water in the SCS experienced more warming at a faster rate than that in the CS for the study period (Fig. 10.1a).
Sea Surface Salinity (SSS)
Changes in sea surface salinity (SSS) can influence both the chemical characteristics of a water mass and the marine ecosystem. The long-term linear changes of SSS in the SCS and the CS were also investigated using the linear fitting method described above. The results indicate that the SSS in most of the SCS has decreased by -0.5 to -0.6 ± 0.087 g kg-1 at a rate of -0.09 to -0.11 g kg-1 decade-1 during 1958-2008 (color shading indicates 95% confidence interval; Fig. 10.1a). In most of the CS, SSS has decreased by -0.2 g kg-1 at a rate of -0.04 g kg-1 decade-1 (grid shading indicates 95% confidence interval; Fig. 10.1b). Similarly, it is easy to see that the surface water in the SCS shows greater freshening at a faster rate than that in the CS (Fig. 10.1b).