Interannual and long-term sea level variability in the eastern Indian Ocean and South China Sea

Abstract

Sea level anomalies (SLAs) derived from satellite observations (over a period of 22 years) and tide gauge data compiled from 66 stations from the eastern Indian Ocean and South China Sea (SCS) and western Pacific Ocean have been analyzed to study the interannual to long term variation of SLAs in the eastern Indian Ocean and SCS. Spatial patterns of sea level variability on the eastern boundary of the Indian Ocean exhibit non-coherent variability with SCS but show coherent variability with western Pacific Ocean. We find coherent variability in interannual SLAs in the Bay of Bengal, Andaman Sea, Malacca Strait and Java Strait. A large fraction of interannual SLA variations in the eastern SCS and interior SCS is linked to El Nino-Southern Oscillation (ENSO) and rest of the region is characterized by small scale interannual variations. The interannual SLAs in the SCS show seasonality with pronounced variation during winter and fall seasons. Interannual surface wind anomalies associated with Indian Ocean Dipole (IOD) and ENSO explain sea level interannual variability in the eastern Indian Ocean and SCS. The decadal sea level variability associated with Pacific Decadal Oscillation (PDO) and decadal ENSO are observed in the SCS.