CoAuthors

Severine Fouriner (JPL, USA); Arnold Gordon (Columbia University, USA); Janet Sprintall (University of California San Diego, USA); Jacqueline Boutin (Sorbonne University, France)

The Indonesian throughflow (ITF) is the only tropical connection of the global ocean circulation, influencing Indo-Pacific oceanic exchanges, climate, biogeochemistry, and Indian Ocean sea level. Meridional sea level gradient along the main channel of the ITF, the Makassar Strait in the Indonesian Seas, is indicative of the pressure gradient that drives the ITF. Effect of regional water cycle on the meridional sea level gradient along this strait is not well understood. Using ocean-atmosphere-land satellite measurements, we found that (1) seasonal variation of upper-layer salinity variation has a major contribution to meridional sea level gradient along the strait, and (2) the seasonal variation of upper-layer salinity is primarily caused by the regional water cycle associated with monsoon-induced precipitation and runoff. We further assess the relation of water cycle, upper-layer salinity, and sea level gradient on interannual time scales.