Enormous aquifer discovered under Greenland ice sheet

Dec 23, 2013 by Maria-José Viñas
Glaciologist Lora Koenig (left) operates a video recorder that has been lowered into the bore hole to observe the ice structure of the aquifer in April 2013. Credit: University of Utah/Clément Miège

Buried underneath compacted snow and ice in Greenland lies a large liquid water reservoir that has now been mapped by researchers using data from NASA's Operation IceBridge airborne campaign.

A team of glaciologists serendipitously found the aquifer while drilling in southeast Greenland in 2011 to study snow accumulation. Two of their ice cores were dripping water when the scientists lifted them to the surface, despite air temperatures of minus 4 F (minus 20 C). The researchers later used NASA's Operation Icebridge radar data to confine the limits of the water reservoir, which spreads over 27,000 square miles (69,930 square km) – an area larger than the state of West Virginia. The water in the aquifer has the potential to raise global by 0.016 inches (0.4 mm).

"When I heard about the aquifer, I had almost the same reaction as when we discovered Lake Vostok [in Antarctica]: it blew my mind that something like that is possible," said Michael Studinger, project scientist for Operation IceBridge, a NASA airborne campaign studying changes in ice at the poles. "It turned my view of the Greenland upside down – I don't think anyone had expected that this layer of liquid water could survive the cold winter temperatures without being refrozen."

Southeast Greenland is a region of high snow accumulation. Researchers now believe that the thick snow cover insulates the aquifer from cold winter surface temperatures, allowing it to remain liquid throughout the year. The aquifer is fed by meltwater that percolates from the surface during the summer.

The new research is being presented in two papers: one led by University of Utah's Rick Forster that was published on Dec. 22 in the journal Nature Geoscience and one led by NASA's Lora Koenig that has been accepted for publication in the journal Geophysical Research Letters. The findings will significantly advance the understanding of how melt water flows through the ice sheet and contributes to sea level rise.

An ice core segment extracted from the aquifer by Koenig's team, with trapped water collecting at the lower left of the core. Credit: NASA's Goddard Space Flight Center/Ludovic Brucker

When a team led by Forster accidentally drilled into water in 2011, they weren't able to continue studying the aquifer because their tools were not suited to work in an aquatic environment. Afterward, Forster's team determined the extent of the aquifer by studying radar data from Operation IceBridge together with ground-based radar data. The top of the water layer clearly showed in the as a return signal brighter than the ice layers.

Koenig, a glaciologist with NASA's Goddard Space Flight Center in Greenbelt, Md., co-led another expedition to southeast Greenland with Forster in April 2013 specifically designed to study the physical characteristics of the newly discovered . Koenig's team extracted two cores of firn (aged snow) that were saturated with water. They used a water-resistant thermoelectric drill to study the density of the ice and lowered strings packed with temperature sensors down the holes, and found that the temperature of the aquifer hovers around 32 F (zero C), warmer than they had expected it to be.

Koenig and her team measured the top of the aquifer at around 39 feet (12 meters) under the surface. This was the depth at which the boreholes filled with water after extracting the ice cores. They then determined the amount of water in the water-saturated firn cores by comparing them to dry cores extracted nearby. The researchers determined the depth at which the pores in the firn close, trapping the water inside the bubbles – at this point, there is a change in the density of the ice that the scientists can measure. This depth is about 121 feet (37 meters) and corresponds to the bottom of the aquifer. Once Koenig's team had the density, depth and spatial extent of the aquifer, they were able to come up with an estimated water volume of about 154 billion tons (140 metric gigatons). If this water was to suddenly discharge to the ocean, this would correspond to 0.016 inches (0.4 mm) of sea level rise.

A thin section of a core extracted from the aquifer by Koenig's team is held in front of the sun. Credit: NASA's Goddard Space Flight Center/Ludovic Brucker

Researchers think that the perennial aquifer is a heat reservoir for the ice sheet in two ways: melt water carries heat when it percolates from the surface down the ice to reach the aquifer. And if the trapped water were to refreeze, it would release latent heat. Altogether, this makes the ice in the vicinity of the aquifer warmer, and warmer flows faster toward the sea.

"Our next big task is to understand how this aquifer is filling and how it's discharging," said Koenig. "The aquifer could offset some if it's storing water for long periods of time. For example after the 2012 extreme surface melt across Greenland, it appears that the aquifer filled a little bit. The question now is how does that leave the aquifer on its way to the ocean and whether it will leave this year or a hundred years from now."

Explore further: Greenland ice stores liquid water year-round

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User comments : 12

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ScooterG
1 / 5 (8) Dec 24, 2013
Maybe there's a volcano under there that's providing heat - but then that wouldn't fit the AGW modus operandi, would it?
Maggnus
4.3 / 5 (6) Dec 24, 2013
Or maybe its exactly what they say it is. Wow imagine that!
ScooterG
1 / 5 (6) Dec 24, 2013
If this discovery did in-fact "turn his view of the Greenland ice sheet upside down", you'd think he would have made mention of other possible reasons and why those reasons were ruled out.

Truth is, they went there on an AGW-oriented mission, and they needed to come home with an AGW-oriented outcome, and so they did.

Follow the money.
barakn
4.2 / 5 (5) Dec 24, 2013
Maybe there's a volcano under there that's providing heat - but then that wouldn't fit the AGW modus operandi, would it?

The aquifer is mostly in a layer of firn near the top of the ice, not in the blue glacial ice down below. The bottom of the aquifer is in the ice layer, not grounded on bedrock. So now you're going to have to invent some sort of post-hoc theory that explains how the volcano's heat skipped the ice layers immediately above it.
ScooterG
1 / 5 (5) Dec 24, 2013
Maybe there's a volcano under there that's providing heat - but then that wouldn't fit the AGW modus operandi, would it?

The aquifer is mostly in a layer of firn near the top of the ice, not in the blue glacial ice down below. The bottom of the aquifer is in the ice layer, not grounded on bedrock. So now you're going to have to invent some sort of post-hoc theory that explains how the volcano's heat skipped the ice layers immediately above it.


Right... The people who made the discovery admit to not knowing much about this "lake", yet you know everything. LMAO
Sigh
5 / 5 (2) Dec 26, 2013
The aquifer is mostly in a layer of firn near the top of the ice, not in the blue glacial ice down below. The bottom of the aquifer is in the ice layer, not grounded on bedrock.


Right... The people who made the discovery admit to not knowing much about this "lake", yet you know everything. LMAO

Quote from the article:
The researchers determined the depth at which the pores in the firn close, trapping the water inside the bubbles – at this point, there is a change in the density of the ice that the scientists can measure. This depth is about 121 feet (37 meters) and corresponds to the bottom of the aquifer.


ScooterG
1 / 5 (4) Dec 27, 2013
I think it's gonna' take more than a few core samples to know anything about a 27,000 square mile lake.

Nice try, yee ever-so-subservient AGW-faithful!
Sigh
5 / 5 (3) Dec 28, 2013
I think it's gonna' take more than a few core samples to know anything about a 27,000 square mile lake.

Nice try, yee ever-so-subservient AGW-faithful!

Nice try at shifting the goal posts.
1) Your hypothesis conflicted with the empirical findings
2) You claimed barakn, who had pointed out the problem with your hypothesis, couldn't know enough
3) You were shown that you had missed the relevant data
4) You carefully avoid being specific about what data you claim is missing, but imply not enough is known and everybody but you is wrong.

Do explain how your hypothesis of a volcano under the ice sheet is consistent with the aquifer not resting on the bedrock.
Maggnus
3.7 / 5 (3) Dec 28, 2013
Asking Scooter to act scientific? Ya good luck with that, it doesn't fit in with his particular view of the conspiracy he thinks all scientists are part of.
ScooterG
1 / 5 (1) Dec 31, 2013
I think it's gonna' take more than a few core samples to know anything about a 27,000 square mile lake.

Nice try, yee ever-so-subservient AGW-faithful!

Nice try at shifting the goal posts.
1) Your hypothesis conflicted with the empirical findings
2) You claimed barakn, who had pointed out the problem with your hypothesis, couldn't know enough
3) You were shown that you had missed the relevant data
4) You carefully avoid being specific about what data you claim is missing, but imply not enough is known and everybody but you is wrong.

Do explain how your hypothesis of a volcano under the ice sheet is consistent with the aquifer not resting on the bedrock.


Apply this level critical thinking to AGW and you'll likely become a denialist.
ScooterG
1 / 5 (1) Dec 31, 2013
Asking Scooter to act scientific? Ya good luck with that, it doesn't fit in with his particular view of the conspiracy he thinks all scientists are part of.


So much of the AGW propaganda is hogwash that to talk science about any of it lends credence where it is not deserved.

You want so bad to have AGW (mentally) associated with science, when in-fact AGW is an abomination on science.

Follow the money.
barakn
1 / 5 (1) Jan 05, 2014
Still convinced climate scientists are driving Rolls-Royces and flashing gold-toothed smiles, huh? People don't go into climate science for the money because there isn't much there. But since money is your god and greed is your prime motivator, you will never be able to grasp this concept.