Figure above: The Indonesian Throughflow (ITF) is a ocean current that flows from the Western Equatorial Pacific north of the equator to 12°S into the Indian Ocean. 90% of the ITF moves through the Makassar Strait. Today, the seasonally relatively fresh, buoyant,  surface layer in the southern Makassar restricts surface flow of  warm  water southward.  The cooler ITF water below the surface layer is not restricted. The net effect is to cool the near surface waters in the Indian Ocean.  In this Figure, the water temperature (top panel: and salinity (bottom panel) shows the cooling (blue colors) and freshening (blue colors) effect of the ITF on the Indian Ocean (Figure modified from Gordon et al., 2005).

I have workied on 2 projects in the Makassar Strait region. (1) Along with my colleagues Yair Rosenthal (Rutgers) and Delia Oppo (WHOI) we used sediments cores to evaluate past changes in the ITF,  Western Pacific Warm Pool (WPWP) surface  conditions and Intermediate water temperatures and heat content at centennial to glacial/interglacial time-scales over the last 30,000 years.  (2) I also worked with Dr. Chris Charles at Scripps and Dr. Tim Rixen at the University of Bremen (Germany) to use modern corals to reconstruct seasonal, interannual and decadal-scale changes in the freshening of the southern Makassar Strait and to evaluate the effects on the ITF.

Linsley, B. K., H. C. Wu, T. Rixen, C. D. Charles, A. L. Gordon, and M. D. Moore, SPCZ Zonal Events and Downstream Influence on Surface Ocean Conditions in the Indonesian Throughflow Region, Geophys. Res. Lett., 43, doi:10.1002/2016GL070985, 2017A (published on-line in December 2016).

Cruise track of Indonesian Sediment Coring Cruise with Yair Rosenthal (Rutgers) and Delia Oppo (Woods Hole Oceanographic Institution) July 2003:  Cores from this cruise are still being analyzed.