Remote energy sources for mixing in the Indonesian Seas.

The role of the Indonesian Seas in climate is attributed to the intense mixing observed throughout the region. Mixing cools the surface temperature and hence modifies the atmospheric convection centered over the region. Mixing also controls the heat exchange between the Pacific and Indian Oceans by transforming water-mass properties while they transit through the region. Mixing in the Indonesian Seas has long been identified to be driven locally by tides. Here we show that the observed mixing can also be powered by the remotely generated planetary waves and eddies. We use a regional ocean model to show that the Indonesian Seas are a sink of the energy generated in the Indian and Pacific Oceans. We estimate that 1.7 GW of the remotely generated energy enters the region across all straits. The energy flux is surface intensified and characterized by a convergence, implying dissipation and mixing, within the straits and along topography. Locally, energy convergence associated with this process is comparable in magnitude to tidal energy dissipation, which dominates the deep ocean.