Indian Ocean Kelvin waves in the Indonesian Throughflow Exit Passages

Equatorial Kelvin waves generated by westerly wind anomalies over the central Indian Ocean propagate eastward to Indonesia, where they can enter the outflow passages of the Indonesian Throughflow (ITF) and affect transports of mass and heat. This has potential consequences for local thermohaline properties and may also be related to larger scale climate modes such as the Indian Ocean Dipole (IOD) and Madden-Julian Oscillation (MJO). Moorings were deployed in Lombok and Ombai Straits, two ITF exit passages, as part of the three-year International Nusantara STratification ANd Transport (INSTANT) program. These data provide the first comprehensive, full-depth, high-resolution measurements of velocity and temperature in the exit passages and have allowed us to thoroughly characterize the properties of Kelvin waves in the throughflow region. Here, we discuss the relationship between ITF Kelvin waves and the structure and timing of the wind forcing over the Indian Ocean. Specifically, we focus on the partitioning of Kelvin wave energy between the ITF outflow passages, mode-1 versus mode-2 vertical structure of the Kelvin waves, and the connection between wind forcing, MJO, IOD, and monsoon dynamics.