Interannual/Interdecadal Variabilities of Sea Surface Height in the South China Sea --Correlation Analysis with ENSO /PDO

Based on merged altimetry data over the period 1993-2011, we investgated the interannual and interdecadal variability of sea surface height (SSH) in the South China Sea (SCS), and discussed their relations to the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). Correlation analysis indicates that interannual component of the SSH anomaly (SSHa) has a significant correlation with the Niño 3.4 index , further proving that SSH in the SCS is closely related to ENSO . The correlation between them presents spatial difference and varies with the seasons. In addition to the ENSO, the PDO has great effect on the interdecadal variability of the SSH in the SCS .The negative phase of the PDO in the last twenty years explains the rise of sea level in the SCS to a great extent. SSH in the SCS rose at a rate of ~4.8 mm/yr during 1993-2011. 70 percent of the trend can be explained by the PDO. After removing the part related to the PDO from the SSHa timeseries, the rise rate is estimated to be ~1.4 mm/yr, indicating that the global warming may be account for only 30% sea level rise in the SCS during 1993-2011.