Interannual-to-decadal variability of sea level in the South China Sea

Interannual-to-decadal variability and trends of sea level in the South China Sea (SCS) are studied using altimetric data during 1993−2012 and reconstructed sea level data from 1950−2009. The interannual variability shows a strong seasonality. Surface wind anomalies associated with El Niño-Southern Oscillation explain the sea-level anomaly pattern in the interior SCS, while Rossby waves radiated from the eastern boundary dominate the sea-level variability in the eastern SCS. Decadal variability of sea level in the SCS follows that in the western tropical Pacific, with large variance found west of Luzon Island. Local atmospheric forcing makes a negative contribution to decadal variability in the central SCS, and Rossby waves radiated from the eastern boundary appear to be important. During 1993−2012, decadal sea level averaged in the SCS is significantly correlated with the Pacific Decadal Oscillation (PDO) (r = −0.96). The decadal variability associated with the PDO accounts for most part of sea-level trends in the SCS in the last two decades.