Mystery Sea Opened Up During the Antarctic Winter. Now, Scientists Know Why.
Source: Live Science
Mystery Sea Opened Up During the Antarctic Winter. Now, Scientists Know Why.
By Stephanie Pappas, Live Science Contributor | April 30, 2019 06:59am ET
A swath of ice-free sea that regularly opens up during the frigid Antarctic winters is created by cyclones.
Sea ice in Antarctica is thickest in the winter, so the appearance of open water is perplexing. These open seas are called polynyas. In 2017, scientists spotted one in the Lazarev Sea, which they called the Maud Rise polynya because it sits over an ocean plateau called Maud Rise.
Now, researchers led by Diana Francis, a New York University Abu Dhabi atmospheric scientist, find that cyclonic winds push ice in opposite directions, causing the pack to open up and expose open sea.
Polar storms
In mid-September 2017, the Maud Rise polynya was 3,668 square miles (9,500 square kilometers) in size. By mid-October, it had grown to 308,881 square miles (800,000 square km).
An analysis of high-resolution satellite imagery explained the rapid growth. Warm, moist air flowing in from the western South Atlantic hit cold air headed northward from the south, setting the stage for violent storms. The resulting cyclones rated 11 on the Beaufort storm scale, meaning they involved wind speeds of up to 72 mph (117 km/h) and waves up to 52 feet (16 meters) high anywhere they encountered open sea.
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Read more: https://www.livescience.com/65361-antarctica-mystery-open-sea.html
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Related: Polar cyclones at the origin of the reoccurrence of the Maud Rise Polynya in austral winter 2017 (JGR Atmospheres)
