TRIUMPH: Transport Indonesian Seas, Upwelling, and Mixing Physics

The Indonesian throughflow (ITF) is a fundamental component of the heat and freshwater budgets of the Pacific and Indian Oceans and the global climate system. Along its pathways through Indonesian seas, ITF experiences strong tidal mixing. The southern coasts of Sumatra-Java-Bali especially are known for upwelling region. In addition, southern Java-Sumatra is one of the centers of Indian Ocean Dipole (IOD). To study all these processes, we have an international collaborative program called TRIUMPH, which is a collaboration between scientists from the Indonesian Institute of Sciences (LIPI), the First Institute of Oceanography (FIO)-China, and University of Maryland (UMD)-USA. The main objectives of this program are (1) To measure and determine the magnitude and variability of full depth transport of water mass, heat and freshwater flux as well as a biogeochemical flux at main ITF inflow (Makassar Strait) and exit passages (Lombok, Bali, and Alas Strait); (2) To measure and determine the mechanisms and processes of tidal mixing and the effects on the water mass transformation along the exit passages of the ITF such the Lombok and Alas Straits; (3) To measure and determine the variability of IOD in the Eastern Indian Ocean and upwelling along the southern coast of Java. During the TRIUMPH cruise in November-December 2019, one surface mooring has been deployed in the center of the IOD region, two subsurface moorings in the southern coast of Java, two subsurface moorings in the Lombok Strait and two subsurface moorings in the Makassar Strait. In addition, three trawl resistant-bottom mounted ADCPs have been deployed in the Bali, Badung, and Alas Strait. Preliminary analysis of TRIUMPH cruise in 2019 will be presented.