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SOCCOM float surfaces inside rare Antarctic sea ice opening


Sea ice and clouds blanket the Weddell Sea around Antarctica in this satellite image from September 25, 2017. A SOCCOM float surfaced within the 60,000 km2 polynya (center) at the location marked in yellow. Image from MODIS-Aqua via NASA Worldview; sea ice contours from AMSR2 ASI via University of Bremen.

Contact: Ethan Campbell, University of Washington

A massive hole in the sea ice cover around Antarctica has been open for the past month1. Known as a polynya, this mysterious opening is the largest observed in the Weddell Sea since the 1970s. In recent studies, SOCCOM-affiliated researchers have used climate models to explore why these polynyas form and how they affect ocean and atmospheric circulation patterns2–5. However, the difficulty of mounting Antarctic expeditions in winter means that few actual measurements have been made of these rare events.

With the array of robotic profiling floats deployed as part of the SOCCOM project, an impromptu Antarctic expedition may not be necessary. Floats can collect ocean measurements year-round, even underneath sea ice. Last month, SOCCOM scientists were astonished to discover that a float in the Weddell Sea had surfaced inside the polynya, making contact with satellites in the dead of winter. Its new ocean measurements, transmitted when it surfaced, are being analyzed as part of a study in preparation on Weddell Sea polynyas. With these new observations comes the possibility that the polynya’s secrets may finally be revealed.

 

References:

1. Stone, M. (2017, October 3). An enormous hole in Antarctica’s sea ice could help solve a climate riddle. Earther. Retrieved from https://earther.com/theres-an-enormousmysterious-hole-in-antarcticas-sea....

2. de Lavergne, C., Palter, J. B., Galbraith, E. D., Bernardello, R. & Marinov, I. Cessation of deep convection in the open Southern Ocean under anthropogenic climate change. Nat. Clim. Chang. 4, 278–282 (2014).

3. Zanowski, H., Hallberg, R. & Sarmiento, J. L. Abyssal ocean warming and salinification after Weddell Polynyas in the GFDL CM2G coupled climate model. J. Phys. Oceanogr. 45, 2755–2772 (2015).

4. Dufour, C. O. et al. Preconditioning of the Weddell Sea polynya by the ocean mesoscale and dense water overflows. J. Clim. 30, 7719–7737 (2017).

5. Cabré, A., Marinov, I. & Gnanadesikan, A. Global atmospheric teleconnections and multidecadal climate oscillations driven by Southern Ocean convection. J. Clim. 30, 8107– 8126 (2017).