AGU: Geophysical Research Letters

 

Editors' Highlight

Ocean supergyre in the Southern Hemisphere

Midlatitude oceanic circulation in the Southern Hemisphere is traditionally thought to consist of basin-wide but distinct gyres contained within the Indian, Pacific, and Atlantic oceans. However, model simulations suggest that these gyres are linked by a global-scale "supergyre" that transfers water to all three ocean basins. From a thorough analysis of temperature and salinity profiles collected since 1950 between 60°S and the equator, Ridgway and Dunn (2007) located this supergyre. Water flows at intermediate depths from the Pacific Ocean to the Indian Ocean through a pathway around Tasmania, an observation supported by models but not fully documented by previous field research until now. Consistent with previous observations, they found that in the upper layers, Pacific Ocean water principally flows through the Indonesian archipelago into the Indian Ocean. Water from the Indian Ocean then leaks into the Atlantic Ocean around the southern tip of Africa. A pathway on the northern edge of the Antarctic Circumpolar Current returns the gyre waters back to the Pacific. The supergyre is a central agent for distributing intermediate water around the global ocean.

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