Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greenland Ice Stores Liquid Water Year-Round

23.12.2013
Potential for Storing Meltwater Important for Calculating Sea-Level Rise

Researchers at the University of Utah have discovered a new aquifer in the Greenland Ice Sheet that holds liquid water all year long in the otherwise perpetually frozen winter landscape. The aquifer is extensive, covering 27,000 square miles.


Evan Burgess, co-author

Drill rig used to extract firn cores from within the Greenland firn aquifer. One of the snowmobiles used in the 186 mile traverse of the ice sheet to reach the drill site.

The reservoir is known as a “perennial firn aquifer” because water persists within the firn – layers of snow and ice that don’t melt for at least one season. Researchers believe it figures significantly in understanding the contribution of snowmelt and ice melt to rising sea levels.

The study was published online Sunday, Dec. 22, in the journal Nature Geoscience.

“Of the current sea level rise, the Greenland Ice Sheet is the largest contributor – and it is melting at record levels,” says Rick Forster, lead author and professor of geography at the University of Utah. “So understanding the aquifer’s capacity to store water from year to year is important because it fills a major gap in the overall equation of meltwater runoff and sea levels.”

Forster’s team has been doing research in southeast Greenland since 2010 to measure snowfall accumulation and how it varies from year to year. The area they study covers 14 percent of southeast Greenland yet receives 32 percent of the entire ice sheet's snowfall, but there has been little data gathered.

In 2010, the team drilled core samples in three locations on the ice for analysis. Team members returned in 2011 to approximately the same area, but at lower elevation. Of the four core samples taken then, two came to the surface with liquid water pouring off the drill while the air temperatures were minus 4 degrees Fahrenheit. The water was found at about 33 feet below the surface at the first hole and at 82 feet in the second hole.

“This discovery was a surprise,” Forster says. “Although water discharge from streams in winter had been previously reported, and snow temperature data implied small amounts of water, no one had yet reported observing water in the firn that had persisted through the winter.”

The aquifer is extensive, covering 27,000 square miles -- larger than the state of West Virginia. It is similar in form to a groundwater aquifer on land that can be used for drinking water. “Here instead of the water being stored in the airspace between subsurface rock particles, the water is stored in the air space between the ice particles, like the juice in a snow cone,” Forster adds. “The surprising fact is the juice in this snow cone never freezes, even during the dark Greenland winter. Large amounts of snow fall on the surface late in the summer and quickly insulates the water from the subfreezing air temperatures above, allowing the water to persist all year long.”

Why Studying Ice in Greenland is Important

The Greenland Ice Sheet is vast, covering roughly the same area as the states of California, Nevada, Arizona, New Mexico, Colorado and Utah combined. The average thickness of the ice is 5,000 feet. In 2012, the ice sheet lost volume of 60 cubic miles – a record for melt and runoff.

The consequences of losing the ice sheet could be catastrophic. If all the water retained in the ice sheet melted, it is estimated that the global sea level would rise about 21 feet, says Forster. Although no one is predicting a total meltoff all at once, keeping an eye on ice formation, runoff amounts and how the water is moving is critical to accurately predicting sea level changes.

Until now, calculations of the ice sheet mass changes did not include a year-round storage mechanism for liquid water. Models predicted that water either flowed into rivers and lakes on the ice surface, into crevasses and subglacial streams that eventually run into the sea, or was refrozen within the ice sheet.

Discovery of the perennial aquifer will help scientists predict the movement and temperature of water within the ice sheet with more precision.

Forster says the reservoir’s exact role is unknown. “It might conserve meltwater flow and thus help slow down the effects of climate change. But it may also have the opposite effect, providing lubrication to moving glaciers and exacerbating ice velocity and calving increasing the mass of ice loss to the global ocean.”

As for whether climate change caused the aquifer to form, Forster says that’s not clear, but simulations of the Greenland Ice Sheet going back to the early 1970s would suggest it has been around for some time.

How the Study was Conducted

The previously unknown storage mode was found in the southeast section of Greenland, where conditions combine to provide sufficient rain and snowmelt to fill the firn with water, as well as high levels of snow accumulation that insulate the water from freezing during the winter.

The team used data collected by airborne and ground-penetrating radar to pinpoint the aquifer, and then took core samples on the ground.

Airborne radar imagery was collected in the area by NASA Operation IceBridge, which is a program directed at collecting images of Earth’s polar ice in unprecedented detail to better understand the processes that connect polar regions with climate change. Ground-penetrating radar and a roving Global Positioning System navigation unit also were towed across the ice in the same area via snowmobile, collecting data every five seconds.

Researchers found that the radar images from air and ground corresponded on both the depth of a bright horizon, indicating where there is a change in consistency of the ice, as well as the undulations of the horizon across distance of about 15 miles. This was confirmation that the airborne radar could map the aquifer just as well as the ground-based radar.

Core samples were taken with a 4-inch-diameter drill. Two segments were extracted that were saturated with liquid water – one from a depth of about 33 feet and another the following day about a mile east and at a depth of more than 80 feet.

Temperatures in the spring of 2011 were below average. Forster notes that, “because air temperatures were minus 4 degrees Fahrenheit during drilling and because surface melting in the area did not begin until June in 2011, there is no doubt that the water found in the firn had persisted through the winter.”

This research is an international collaboration among researchers at the University of Utah, the Geological Survey of Denmark and Greenland, Byrd Polar Research Center at the Ohio State University, Institute for Marine and Atmospheric Research Utrecht, Utrecht University, the NASA Goddard Space Flight Center, the Center for Remote Sensing of Ice Sheets at the University of Kansas, and the Desert Research Institute at the University of Nevada, Reno. Forster and the Utah team were supported by the National Science Foundation and NASA.

After the embargo expires, this news release and photos may be downloaded here:
http://unews.utah.edu/news_releases/greenland-ice-stores-liquid-water-year-round/

Video of water from the Greenland perennial firn aquifer draining from a core extracted 33 feet below the surface of the ice sheet. http://youtu.be/7VEpJpCvrbI

Before the embargo expires, media may use the case-sensitive password: Greenland

Richard R. Forster, professor of geography – office 801-581-8620, cell 801-450-3689, rick.forster@geog.utah.edu

Valoree Dowell | Newswise
Further information:
http://www.utah.edu

More articles from Earth Sciences:

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

nachricht Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>