Hole the Size of Maine Opens in Antarctica Ice
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by gardenmaeve moderator
Hole the Size of Maine Opens in Antarctica Ice - This is the first time scientists have observed a hole of this magnitude since the 1970s.
(Refers to the State of Maine, in Northeastern United States of America.)
By Heather Brady PUBLISHED October 11, 2017A mysterious hole as big as the state of Maine has been spotted in
Antarctica’s winter sea ice cover.The hole was discovered by researchers about a month ago. The team,
comprised of scientists from the University of Toronto and the
Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM)
project, was monitoring the area with satellite technology after a
similar hole opened last year.Known as a polynya, this year’s hole was about 30,000 square miles at
its largest, making it the biggest polynya observed in Antarctica’s
Weddell Sea since the 1970s.“In the depths of winter, for more than a month, we’ve had this area
of open water,” says Kent Moore, professor of physics at the
University of Toronto. “It’s just remarkable that this polynya went
away for 40 years and then came back.”The harsh winter in Antarctica makes it hard to find holes like this
one, so it can be difficult to study them. This is the second year
that a polynya formed, though last year’s hole was not as big.
Scientists knew to monitor the area for polynyas this year because of
last year’s discovery.The deep water in that part of the Southern Ocean is warmer and
saltier than the surface water. Ocean currents bring the warmer water
upwards, where it melts the blankets of ice that had formed on the
ocean’s surface. That melting created the polynya.Since the hole continually exposes the water to the atmosphere above,
it is difficult for new ice layers to form. When the warmer water
cools, on contact with the frigid temperatures in the atmosphere, it
sinks. Then it reheats in deeper areas, allowing the cycle to
continue.Moore says they are working to understand what is triggering the
formation of these holes again after so many years. He thinks it is
likely that marine mammals could be using this new opening to breathe.The cooling of the warmer ocean water when it reaches the surface may
also have a broader impact on the ocean’s temperature, but Moore says
outside of local weather effects, scientists aren’t sure what this
polynya will mean for Antarctica’s oceans and climate, and whether it
is related to climate change.“We don’t really understand the long-term impacts this polynya will
have,” he says.Posted
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by yshish moderator, translator in response to gardenmaeve's comment.
Thanks for sharing, @gardenmaeve
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by AvastMH moderator
Hi @gardenmaeve - sorry I didn't spot this until today. I find polynyas very peculiar and quite worrying. They are not new in the history of polar ice, but I hope these are not yet another sad sign of an over-cooked planet 😕
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by AvastMH moderator
A very interesting piece about the Greenland Icesheet and its melting state sent to me by Edyflwr - Thank you @edyflwr 😃
https://www.nytimes.com/interactive/2017/12/05/climate/greenland-ice-melting.html
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by AvastMH moderator
This news article makes the polynya story above even more fascinating. Scientists have discovered that the Ross Ice-shelf in Antarctica is freezing at its base and not thawing...here's a link to the story....
The Ross Ice Shelf is Freezing, Not Melting. Which Is Weird.
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