Simulating Turbulent Mixing in the Abyssal Waters of the Equatorial Pacific Ocean

Since the Industrial Revolution, nearly 90% of the excess heat trapped by greenhouse gasses and around half of the carbon released by humans have entered the ocean. Knowing where and for how long this heat and carbon is stored in the ocean is critical for predicting climate variability, and is strongly shaped by the ocean’s abyssal circulation. A key branch of this circulation upwells water from the deep equatorial Pacific and is driven by turbulent mixing. However, the source of this turbulence is not well understood. We hypothesize that the turbulence is generated by a type of wave found in the equatorial oceans that breaks upon reflection off the sea-floor after propagating downwards from the surface. The hypothesis is supported by a scant few observations of deep mixing in the equatorial Pacific, however questions remain regarding the strength and spatial extent of the mixing and its impact on the large-scale circulation and hence climate. This collaborative project brings together oceanographers from Stanford University and the Université de Bretagne Occidentale to address these questions by simulating the turbulent mixing in the deep Pacific using a state-of-the-art computer model capable of capturing the physics of the waves, circulation, and mixing.