How openings in Antarctic sea ice affect worldwide climate

In a new analysis of climate models, researchers

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from the University of Pennslyvania, Spain's Institute of Marine Sciences and Johns Hopkins University reveal the significant global effects that these seemingly anomalous polynyas can have. Their findings indicate that heat escaping from the ocean through these openings impacts sea and atmospheric temperatures and wind patterns around the globe and even rainfall around the tropics. Though this process is part of a natural pattern of climate variability, it has implications for how the global climate will respond to future anthropogenic warming.

"This small, isolated opening in the sea ice in the Southern Ocean can have significant, large-scale climate implications," said Irina Marinov, a study author and assistant professor in Penn's Department of Earth and Enviromental Science in the School of Arts & Sciences. "Climate models suggest that, in years and decades with a large polynya, the entire atmosphere warms globally, and we see changes in the winds in the Southern Hemisphere and a southward shift in the equatorial rain belt. This is attributable to the polynya."

The study appears in the Journal of Climate. Marinov coauthored the work with Anna Cabre, a former postdoc in Marinov's lab and now an oceanographer with the Institue of Marine Sciences in Barcelona, and Anand Gnanadesikan, a professor in the Department of Earth and Planetary Science at Johns Hopkins.

Typically, the Southern Ocean is covered in ice during the Southern Hemisphere's

winter. Polynyas occur when warm subsurface waters of North Atlantic and equatorial origin mix locally with cold surface waters, a process known as open-ocean convection.

https://phys.org/news/2017-09-antarctic-sea-ice-affect-worldwide.html