Sea Surface Salinity Near The Maritime Continent

The Indonesian Throughflow (ITF) is the only low-latitude gateway for export of large amounts of heat and freshwater from the Pacific to the Indian Ocean. The ITF affects the atmosphere–ocean coupling with potential impacts on the ENSO (El Niño–Southern Oscillation) and Asian monsoon. On average, 15 million cubic meters per second (15 Sverdrup) of the Pacific Ocean water enters the Indian Ocean, regulating mean state and the overturning circulation of the Indian and Pacific Oceans. The flow passes through several passages. The complex system of these passages is not well resolved in most earth system models used for climate prediction, resulting in a misrepresentation of the transport through the ITF.

The Goddard Earth Observing System (GEOS) atmospheric model coupled with Massachusetts Institute of Technology general circulation (MITgcm) ocean model is used to simulate a time-span of 14 months starting from Jan 20th, 2020. The horizontal resolution of the model in the atmosphere is about 6-7 km atmosphere, and in the ocean is 2-4 km ocean, which better resolves the flow through the narrow sea straits. The resolution allows sub-mesoscale features such as eddies to be captured. The animation of Sea Surface Salinity reveals the detailed spatial and temporal changes in the flow of freshwater.

The majority of this work was done between March to July 2023 while the lead visualizer was at the GMAO.