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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. [ABSTRACT FROM AUTHOR]

The correlation between sea surface temperature (SST) and El Niño-Southern Oscillation (ENSO) persists into post-ENSO September over the South China Sea (SCS), the longest correlation in the World Ocean. Slow modulations of this correlation are analyzed by using the International Comprehensive Ocean-Atmosphere Dataset (ICOADS). ENSO's influence on SCS SST has experienced significant interdecadal changes over the past 138 years (1870-2007), with a double-peak structure correlation after the 1960s compared to a single-peak before the 1940s. According to the ENSO correlation character, the analysis period is divided into four epochs. In epoch 3, 1960-83, the SST warming and enhanced precipitation over the southeastern tropical Indian Ocean, rather than the Indian Ocean basinwide warming, induce easterly wind anomalies and warm up the SCS in the summer following El Niño. Besides the Indian Ocean effect, during epochs 2 (1930-40) and 4 (1984-2007), the Pacific-Japan (PJ) pattern of atmospheric circulation anomalies helps sustain the SCS SST warming through summer (June-August) with easterly wind anomalies. The associated increase in shortwave radiation and decrease in upward latent heat flux cause the SCS SST warming to persist into the summer. Meanwhile, the rainfall response around the SCS to ENSO shows interdecadal variability, with stronger variability after the 1980s. The results suggest that both the remote forcing from the tropical Indian Ocean and the PJ pattern are important for the ENSO teleconnection to the SCS and its interdecadal modulations. [ABSTRACT FROM AUTHOR]