Explaining the Weddell Polynya--a Large Ocean Eddy Shed at Maud Rise

• Published in: Science
• Main Author: Holland, D. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2001
• Subjects: Maud Rise; Weddell; Weddell Sea; Antarc*; Antarctica; Sea ice
• Online Access: http://dx.doi.org/10.1126/science.1059322; https://www.science.org/doi/pdf/10.1126/science.1059322

Satellite observations have shown the occasional occurrence of a large opening in the sea-ice cover of the Weddell Sea, Antarctica, a phenomenon known as the Weddell Polynya. The transient appearance, position, size, and shape of the polynya is explained here by a mechanism by which modest variations in the large-scale oceanic flow past the Maud Rise seamount cause a horizontal cyclonic eddy to be shed from its northeast flank. The shed eddy transmits a divergent Ekman stress into the sea ice, leading to a crescent-shaped opening in the pack. Atmospheric thermodynamical interaction further enhances the opening by inducing oceanic convection. A sea-ice–ocean computer model simulation vividly demonstrates how this mechanism fully accounts for the characteristics that mark Weddell Polynya events.