The hole that opens in Antarctica is caused by invisible air flows.

A huge hole mysteriously appeared out of nowhere in 1973 in the sea ice off the coast of Antarctica. While it looked like an ordinary hole, it was huge enough to swallow the entire state of California.

What exactly is this mysterious hole?

The mysterious hole existed for the next three winters and then apparently began to disappear. It resurfaced once again in 2017 and had a mouth size equal to that of Maine. This huge state-sized hole is known as a polynya. It is an open sea region shrouded in sea ice. It is the exact opposite phenomenon of an iceberg. However, the huge Weddell Polynya – located atop the Maud Rise ocean plateau in the Weddell Sea waters of the Southern Ocean – is a latest example of this rare phenomenon. Its sudden and rare appearance has been a puzzle for scientists for a long time.

In 2019, researchers suggested that the appearance of this polynya depended on the mere coincidence of multiple climate anomalies occurring simultaneously. Another study in the same year, with Diana Francis as the lead scientist, proposed that one of these numerous anomalies were scars from severe cyclones caused by circulation in the atmosphere. It is capable of pulling sea ice opposite and away from the eye of the storm, causing the hole to open.

Factors causing the appearance of polynya

Francis, who now works as a senior scientist at Khalifa University in the UAE, revealed in his latest study that another anomaly responsible for the giant opening is the atmospheric rivers of warm, humid air. This anomaly has been completely neglected until now. In his latest study, Francis and his colleagues have been analyzing data since the 1970s. They found that these streams of hot air were likely responsible for the appearance of holes in 1973 and 2017. Both of these years experienced strong, tenacious streams which confirmed their theory.

Francis said: “I was surprised to see virtually immediate softening in the sea ice covered by these atmospheric rivers during the coldest months of the year in Antarctica.” The researcher thinks that atmospheric rivers caused a flow of warm, humid air from the coast of South America to the polar region. It caused sea ice melting with many other effects such as the release of heat into the air, a local greenhouse effect and a supplement to the cyclone dynamics.

Although these results are not the purpose of understanding the sudden appearance of the Weddell Polynya, but it clearly broadens our knowledge about it. Since both atmospheric rivers and cyclones are assumed to increase as temperatures rise, we may see this opening in Antarctica much more often. The results are reported in Advances in science.