Ocean Sciences Research Spotlight

Contribution of Weddell Gyre to Global Overturning Circulation

How much does the Weddell Gyre contribute to the Global Overturning Circulation?


The Southern Ocean plays a pivotal role in the Global Overturning Circulation (GOC), which transports warm, light water from the tropics to the poles, where it becomes cool, dense, and capable of influencing the global transport of carbon, nutrients, and energy.

Sea ice in the Weddell Sea
Sea ice in the Weddell Sea. Photo: Loic Jullion

One component of the Southern Ocean, the Weddell Gyre, is a rotating region of water that is thought to be the main source of the densest water mass in the ocean—Antarctic Bottom Water (AABW). The movement of AABW has a large influence on overall water movement through the GOC. Jullion et al. suggest, however, that previous research that shows simple influxes and outpouring of water from the Weddell Gyre may be oversimplistic and that the dynamics of the region are far more complicated. To learn more, the authors analyzed 5 years’ worth of data—on temperature, salinity, and movement of water—from the Weddell Gyre to create a model describing its dynamics. The authors found that a significant portion of the AABW may originate in the Indian Ocean and then is transported, recycled, and shifted equatorward by the Weddell Gyre, rather than originating in the gyre itself. Thus, the authors suggest that to fully understand the Weddell Gyre’s contribution to the GOC, future researchers must investigate the Indian Ocean’s contribution to the AABW. (Journal of Geophysical Research: Oceans, doi:10.1002/2013JC009725, 2014)

—JoAnna Wendel, Writer

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