Published: Thu, October 12, 2017
Research | By Raquel Erickson

Massive Hole Has Opened Up in Antarctica

Massive Hole Has Opened Up in Antarctica

"It's just remarkable that this polynya went away for 40 years and then came back".

The Weddell Polynya was first spotted in satellite observations during the mid-1970s. That's a fairly straightforward explanation, but it doesn't fully address the odd timing of the hole, including its 40-year absence and seemingly spontaneous rebirth.

Although winter is in full swing right now in Antarctica, a large swath of water in the Weddell sea is ice-free.

The gap, measuring about 80,000kmat the largest, was detected far from the edge of the ice last month (early September) when scientists were monitoring the area with satellite technology. Scientists measured that the huge sea ice hole or polynya is nearly 80,000 square kilometers at its peak- a little bigger than New Brunswick and a bit smaller than the island of Newfoundland. The polynya is the dark region of open water within the ice pack.

Areas of open water enveloped by ice, such as this hole are known as polynias and are formed in the coastal areas of Antarctica.

"It looks like you just punched a hole in the ice", atmospheric physicist Kent Moore, a professor at the University of Toronto Mississauga, explained. The polynya's occurrence confirms what scientists had previously calculated, and they want to know what made the hole reopen for two years in a row after four decades of not being there.

'We're still trying to figure out what's going on'. In case of this giant hole, it is odd that it has formed "deep in the ice pack".

It's larger than The Netherlands, and almost the size of Lake Superior. According to Moore, the hole is a result of other processes that aren't understood yet.

'This is like opening a pressure relief valve - the ocean then releases a surplus of heat to the atmosphere for several consecutive winters until the heat reservoir is exhausted'. Such ice-free areas are called 'polynya' (Russian) by polar scientists.

Usually, a very cold but fresh layer of water covers a warmer and saltier layer of water, acting as insulation.

Still, it's unclear how often the Weddell Polynya re-emerges, and how long it will linger now that it's opened back up.

Scientific reference: Mojib Latif et al, Southern Ocean Decadal Variability and Predictability, Current Climate Change Reports (2017).

"Global warming is not a linear process and happens on top of internal variability inherent to the climate system".

"We don't really understand the long-term impacts this polynya will have", he says.

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