Trends of sea level variations in the Indo-Pacific warm pool

The long-term trends of sea level height in the Indo-Pacific warm pool (IPWP) were examined using merged altimetry data, and possible mechanisms were studied using multiple datasets. Sea level in the IPWP and the Western Pacific warm pool (WPWP) has distinct interannual variabilities related to ENSO (El Niño–Southern Oscillation) event. The mean sea level in the IPWP has a rising rate of 4.5 mm/yr over the 1993–2005 period, while the WPWP and the Indian Ocean warm pool (IOWP) have rising rate of 6.0 mm/yr and 1.6 mm/yr respectively. The trends of thermosteric sea level were also examined using Ishii data and MITgcm assimilation data and the results indicate that thermal change of upper layer has a significant contribution to the sea level variations in the WPWP. But the thermosteric sea level has little contribution to sea level change in the IOWP region. Apart from thermal contribution, the contribution of precipitation and evaporation to sea level change were also examined.