A mysterious hole as big as the state of ME has been spotted in Antarctica's winter sea ice cover.
Since the hole continually exposes the water to the atmosphere above, it is hard for new ice layers to form. They are known as "polynyas" and traditionally form near coasts in polar regions.
A giant hole has opened up in Antarctica that could possibly be as big as the state of ME (91,646 km²) and Lake Superior (82,103 km²). "If we didn't have a satellite, we wouldn't know it was there".
The Weddell Polynya was first spotted in satellite observations during the mid-1970s.
'For us this ice-free area is an important data point which we can use to validate our climate models, ' says Dr Torge Martin, meteorologist and climate modeller in the GEOMAR Research Division 'Oceans Circulation and Climate Dynamics'. It's the largest polynya to open in the Weddell Sea since the 1970s.
Lead Image: Winter sea ice blankets the Weddell Sea around Antarctica with massive extra-tropical cyclones hovering over the Southern Ocean in this satellite image from September 25, 2017.
'A very cold but relatively fresh water layer covers a much warmer and saltier water mass, thus acting as an insulating layer.
The latest technology allows them to study the polynya even if their access to the site itself in the Southern Ocean is insufficient. In certain conditions, however, the warm water can rise to the surface, melting the ice. "The ocean then releases a surplus of heat to the atmosphere for several consecutive winters until the heat reservoir is exhausted".
What scientists don't yet understand is how often the polynya occurs and why it has occurred twice in the past two years after being dormant for over four decades.
'This is now the second year in a row it's opened after 40 years of not being there, ' Moore explained.
Blaming climate change for this giant hole is one alternative that the scientists have but according to Moore, that would be a premature thing. "Denser, colder water sinks to the bottom of the ocean, while warmer water comes to the surface, which can keep the polynia open once it starts". However, previous other studies which applied the "Kiel Climate Model" found that polynya is part of a long-term naturally varying process, which can only mean the hole will open again sooner or later.
'Global warming is not a linear process and happens on top of internal variability inherent to the climate system, ' Latif says. "The better we understand these natural processes, the better we can identify the anthropogenic impact on the climate system", said Professor Latif.