A study into how the Pacific Ocean leaks into the Indian Ocean has revealed details which researchers say could improve climate predictions.
This so-called Tasman leakage in the south of Australia is the second-largest link between the Pacific and Indian oceans after the Indonesian through-flow to the country's north, according to an international team led by University of New South Wales.
Water travels through the world's oceans along great loops driven by massive and often deep currents in a process known as the global thermohaline circulation, said the study's lead author, Dr Erik Van Sebille. Acting over millennial time scales, the global thermohaline circulation can exert significant influence on global climate variability.
Because the Tasman leakage acts as a bottleneck in the Pacific-to-Indian flow, changes in this pathway can have significant impact on the global thermohaline circulation, say the researchers.
Additionally, the Tasman leakage could also have a direct effect on both the regional Australian climate and the availability of nutrients in the waters of Great Australian Bight, which in turn could affect marine ecosystems in these areas, the Geophysical Research Letters journal reported. Better understanding of this bottleneck in the global ocean has the potential to improve the accuracy of climate predictions, say the researchers. The team used a high-resolution ocean circulation model to determine how much of the water flowing in the East Australia Current eventually ends up in the Indian Ocean. According to the model, most of the water that runs southward along the coasts of Queensland and New South Wales veers east before reaching Bass Strait and stays within the Pacific Ocean.
The remaining fraction comprising the Tasman leakage continues flowing south, rounds Tasmania and then flows west through the Great Australian Bight until it reaches Cape Leeuwin and enters the Indian Ocean.