A giant hole the size of Kansas appeared in the Antarctic ice in 2017 and scientists now know why

In 2017, a giant hole appeared in the Antarctic ice. It appeared in mid-September and initially measured 3700 square miles. In six weeks, it reached more than 30,000 square miles – an area almost as large as that of Kansas.

Known as a polynya, the hole was a zone of unfrozen ocean surrounded by ice. The latter, known as the Maud-Rise Polynya, located in the Lazarev Sea, was first recorded in 1974, but had not been seen since. It has been spotted during the depths of the Antarctic winter, when the sea ice is at its thickest.

What caused its opening was a mystery.

It had already been suggested that the polynyas that appear in winter were caused by winds blowing on the ice – but we do not understand exactly what makes them appear.

In a study published in the Journal of Geophysical Research: Atmospheres, Scientists, led by Diana Francis of New York University, discovered that cyclones were at the root of the phenomenon.

The team used satellite observations and high resolution data about the time and space of the polynya to determine the conditions that led to the hole.

Maud Rise Polynya of September 2017 seen from the space. SCAR ATLAS

They discovered that intense cyclones and high winds had displaced the region's ice. The cyclones they found were comparable to grade 11 on the Beaufort scale. Surface winds cause sea ice to the left, while cyclonic winds drag them in the opposite direction. This led to an opening in the pack ice near the center of the cyclone.

The Maud-Rise polynya grew and grew until its merger with the ocean, as the ice began to retreat in the wake of the beginning of summer.

The researchers say that the link between cyclones and polynyas has consequences for the future because climate change patterns suggest that there will be more polar cyclones in the future.

"The mid-sea polynyas are important because of the heat exchange between the ocean and the atmosphere resulting from their appearance, especially during the winter months, when the pack ice is expected to consolidate. the atmosphere too, "said Francis Newsweek.

After the opening of the polynya, it transfers huge amounts of energy between the ocean and the atmosphere – with the potential to change the climate globally because of its impact on ocean circulation.

That's what Francis will work on next: "My goal will be to look at other sea polynyas and see if the same mechanism is at the origin of their opening," she said. declared. "I would also like to examine the frequency of all polynyas on the high seas around Antarctica and related to cyclone activity during the winters."