The 2017 polynya. (NASA)ENVIRONMENT

https://www.sciencealert.com/invisible-rivers-of-air-flowing-in-the-sky-are-leaving-giant-holes-in-antarctic-ice

PETER DOCKRILL12 NOVEMBER 2020

It appeared in 1973, seemingly out of nowhere: a hole in the sea ice off the coast of Antarctica. But this was no ordinary hole. It was so big it couldswallow California.

The mysterious opening remained in place for the following three winters. Then it seemed to largely disappear before emerging again in 2017, with a giant mawthe size of Maine.

This giant hole with a sometimes state-sized appetite is what’s called apolynya– an area of open water surrounded by sea ice, kind of like the opposite of an iceberg.

But the mysteriousWeddell Polynya– occurring above the oceanic plateau of Maud Rise, in the Weddell Sea waters of the Southern Ocean – is a rather extreme example of this environmental phenomenon. Why it opens up so dramatically and yet so infrequently…