Science Team Finds Melt Lakes, Moulins, Glacial Rivers Atop East Antarctic Ice Sheet - WP

[hatrack]

Atop the ice sheet covering the Arctic island of Greenland, you now see dramatic melting in the summer. It forms lakes, rivers and even dangerous “moulins” in the ice where rivers suddenly plunge into the thick ice sheet, carrying water deep below. East Antarctica is supposed to be different. It is extremely remote and cold. It doesn’t see such warm temperatures in the summer — yet — and so its ice tends to remain more pristine.

“Many people refer to East Antarctica as being too cold for significant melt,” says Jan Lenaerts, a glaciologist with the Utrecht University in the Netherlands. “I mean there’s marginal melt in summer, but there’s not a lot.” That’s the common wisdom, at least, but it is challenged in a new study in Nature Climate Change, by Lenaerts and his colleagues from universities in the Netherlands, Belgium, and Germany. They do so based on research they conducted atop the very large Roi Baudouin ice shelf in East Antarctica, which floats atop the ocean, and where they found a very Greenland-like situation in early 2016.

The researchers had traveled to investigate what had been described as a nearly 2 mile wide “crater” in the shelf, glimpsed by satellite, which some sources believed had been caused by a meteorite. To the contrary, they found that it was a large, 10 foot deep, icy lake bed. In its center, meanwhile, were multiple rivers and three moulins that carried water deep down into the floating ice shelf.

And even this, perhaps, was not the most dramatic finding. The researchers also drilled through the ice and found what they called “englacial” lakes, sandwiched between the surface of the ice shelf and its base, which is in contact with the ocean beneath it. They found 55 lakes in total on or in the ice shelf, and a number of them were in this buried, englacial format. The video of one such discovery, of a crystal blue lake four meters below the ice shelf surface, is shown above, and an image from the video is below:

EDIT

https://www.washingtonpost.com/news/energy-environment/wp/2016/12/12/this-dazzling-antarctic-lake-is-buried-in-floating-ice-and-that-has-scientists-worried/?utm_term=.2f005a40274e

[SamKnause]

1. What do I type in to get around the paywall ???

[hatrack]

2. Darned if I know - it worked for me down through Comments . . .

[SamKnause]

3. I found some photos on a different site, but I wanted

to see the video.

I have used my quota of free articles this month.

I tried twice and got the same message.

Have a great day.

[petronius]

4. I have found--in Firefox at least--that clearing history and cookies seems to

reset that count of monthly articles. And maybe the 'do not track' setting is helping. (I have my browser set to clear everything whenever I close it and to always send the no-track-me message, and I generally don't log in to the papers I subscribe to; the 5-article limit seems to restart every day...)

[OKIsItJustMe]

5. Try going to a different source, closer to the primary source

https://www.kuleuven.be/english/news/2016/mysterious-crater-on-antarctica-is-indication-of-vulnerable-ice-sheet

[font face=Serif][font size=5]Mysterious ‘crater’ on Antarctica is indication of vulnerable ice sheet[/font]

[font size=4]12 December 2016 - The East Antarctic ice sheet appears to be more vulnerable than expected, due to a strong wind that brings warm air and blows away the snow. That is the conclusion reached by a team of climate researchers led by Jan Lenaerts (Utrecht University/KU Leuven) and Stef Lhermitte (TU Delft/KU Leuven), based on a combination of climate models, satellite observations and on-site measurements. “Tens of meters of rising sea levels are locked away in Antarctica”, says Lenaerts. “And our research has shown that also East Antarctica is vulnerable to climate change.”[/font]

[font size=3]Current IPCC projections show large uncertainties in Antarctica’s contribution to sea level rise, because the role of ice shelf processes remains uncertain. Lenaerts explains: “Little climate change is observable in East Antarctica, because the area is so isolated from the rest of the world.” However, to the researchers’ astonishment, the ice shelves in some regions of East Antarctica are melting faster than scientists had previously assumed. These ice shelves appear to be extremely sensitive to climate change.

Hotspots

Through a unique combination of field work, satellite data and a climate model, the researchers were able to explain why some parts of the East Antarctica ice shelves are melting so rapidly. This is because the strong and persistent wind transports warm, dry air to the region, and blows away the snow. This darkens the surface, which subsequently absorbs more of the sun’s heat. The result is a local warmer microclimate with a few literal ‘hotspots’. Because the ice shelf is floating in the ocean, its melting does not immediately contribute to sea level rise. However, the ice shelves around Antarctica are extremely important for ice sheet stability, because they hold back the land ice. If the ice shelves collapse, this land ice ends up in the ocean and consequently sea level will rise.

…

Mysterious crater

Part of the research conducted by Lenaerts and Lhermitte focused on a mysterious crater that was spotted on the King Baudoin ice shelf. “At the time, the media reported that it was probably a meteorite impact crater”, Lenaerts says. “My response was: in that area? Then it’s definitely not a meteorite; it’s proof of strong melting.”

…

In January 2016, the researchers visited the crater and discovered that it was a collapsed lake, with a moulin – a hole in the ice– which allowed the water to flow into the ocean. Lhermitte: “That was a huge surprise. Moulins typically are observed on Greenland. And we definitely never see them on an ice shelf.” Moreover, the researchers discovered that there were many meltwater lakes hidden under the surface of the ice, some of which were kilometres across. Underwater video images provide a clear image of the amount of meltwater present in the area.

…[/font][/font]

(Follow the link for a number of images.)

[NNadir]

6. Nature Climate Change has made the original article open source for viewing only.

You cannot save the article, but you can read it: Nature Climate Change (2016) doi:10.1038/nclimate3180

Otherwise, you can go to a research university library and access it.

I hope this helps.