Collaborative Research: Measurements and Modelling of the Indonesian Throughflow International Experiment (MINTIE)
Located near the largest global centers of atmospheric deep convection and featuring the only inter-basin tropical connection in the global overturning circulation, the Indonesian seas play a fundamental role in the coupled climate system. Pacific Warm Pool waters are cooled and freshened in the Indonesian seas to form a unique water mass that can be tracked across the Indian Ocean basin and beyond. Tidally-driven mixing plays a critical role in this transformation and impacts regional upwelling, sea surface temperature (SST) patterns and thus global climate. Since the highly successful INSTANT program delivered a step change in our understanding of the Indonesian Throughflow (ITF) over 12 years ago, sparse ongoing observations and regional modelling studies have exposed our remaining knowledge gaps. In particular, we have little knowledge on how the interplay between the ITF, incoming remotely-forced wind-driven planetary wave energy and locally generated internal tidal waves and the mixing they produce impacts export heat and freshwater fluxes and SST. Addressing these issues requires more detailed observations of internal hydrography, mixing rates and inflowing/outflowing heat and freshwater fluxes. In addition, since the end of INSTANT in 2006, a significant shift has occurred in the Indo-Pacific system, and likely also the ITF.
This project includes: In early 2021 we are planning a 3-year deployment of a transport and water mass resolving mooring array within the major ITF passages, simultaneous profiling Argo type float sampling the hydrography, dissipation and fine-scale shear in the interior seas, as well as ship-based detailed surveys in the ITF straits. MINTIE will also employ state-of-the-science simulations and diagnostic tools in combination with the observations, to probe the drivers and dynamics of the ITF pathways and variability.