Medical and Hospital News  
ICE WORLD
OMG, the water's warm! NASA study solves glacier puzzle
by Carol Rasmussen for NASA Earth Science News
Washington DC (SPX) Jun 25, 2018

illustration only

A new NASA study explains why the Tracy and Heilprin glaciers, which flow side by side into Inglefield Gulf in northwest Greenland, are melting at radically different rates.

Using ocean data from NASA's Oceans Melting Greenland (OMG) campaign, the study documents a plume of warm water flowing up Tracy's underwater face, and a much colder plume in front of Heilprin. Scientists have assumed plumes like these exist for glaciers all around Greenland, but this is the first time their effects have been measured.

The finding highlights the critical role of oceans in glacial ice loss and their importance for understanding future sea level rise. A paper on the research was published June 21 in the journal Oceanography.

Tracy and Heilprin were first observed by explorers in 1892 and have been measured sporadically ever since. Even though the adjoining glaciers experience the same weather and ocean conditions, Heilprin has retreated upstream less than 2.5 miles (4 kilometers) in 125 years, while Tracy has retreated more than 9.5 miles (15 kilometers). That means Tracy is losing ice almost four times faster than its next-door neighbor.

This is the kind of puzzle OMG was designed to explain. The five-year campaign is quantifying ice loss from all glaciers that drain the Greenland Ice Sheet with an airborne survey of ocean and ice conditions around the entire coastline, collecting data through 2020. OMG is making additional boat-based measurements in areas where the seafloor topography and depths are inadequately known.

About a decade ago, NASA's Operation IceBridge used ice-penetrating radar to document a major difference between the glaciers: Tracy is seated on bedrock at a depth of about 2,000 feet (610 meters) below the ocean surface, while Heilprin extends only 1,100 feet (350 meters) beneath the waves.

Scientists would expect this difference to affect the melt rates, because the top ocean layer around Greenland is colder than the deep water, which has traveled north from the midlatitudes in ocean currents.

The warm water layer starts about 660 feet (200 meters) down from the surface, and the deeper the water, the warmer it is. Naturally, a deeper glacier would be exposed to more of this warm water than a shallower glacier would.

When OMG Principal Investigator Josh Willis of NASA's Jet Propulsion Laboratory in Pasadena, California, looked for more data to quantify the difference between Tracy and Heilprin, "I couldn't find any previous observations of ocean temperature and salinity in the fjord at all," he said. There was also no map of the seafloor in the gulf.

OMG sent a research boat into the Inglefield Gulf in the summer of 2016 to fill in the data gap. The boat's soundings of ocean temperature and salinity showed a river of meltwater draining out from under Tracy.

Because freshwater is more buoyant than the surrounding seawater, as soon as the water escapes from under the glacier, it swirls upward along the glacier's icy face.

The turbulent flow pulls in surrounding subsurface water, which is warm for a polar ocean at about 33 degrees Fahrenheit (0.5 degree Celsius). As it gains volume, the plume spreads like smoke rising from a smokestack.

"Most of the melting happens as the water rises up Tracy's face," Willis said. "It eats away at a huge chunk of the glacier."

Heilprin also has a plume, but its shallower depth limits the plume's damage in two ways: the plume has a shorter distance to rise and gathers less seawater; and the shallow seawater it pulls in has a temperature of only about 31 degrees Fahrenheit (minus 0.5 degree Celsius).

As a result, even though Heilprin is a bigger glacier and more water drains from underneath it than from Tracy, its plume is smaller and colder.

The study produced another surprise by first mapping a ridge, called a sill, only about 820 feet (250 meters) below the ocean surface in front of Tracy, and then proving that this sill did not keep warm water from the ocean depths away from the glacier.

"In fact, quite a lot of warm water comes in from offshore, mixes with the shallower layers and comes over the sill," Willis said. Tracy's destructive plume is evidence of that.


Related Links
NASA's Oceans Melting Greenland
Beyond the Ice Age


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


ICE WORLD
What saved the West Antarctic Ice Sheet 10000 years ago will not save it today
Potsdam, Germany (SPX) Jun 14, 2018
The retreat of the West Antarctic ice masses after the last Ice Age was reversed surprisingly about 10,000 years ago, scientists found. This is in stark contrast to previous assumptions. In fact it was the shrinking itself that stopped the shrinking: relieved from the weight of the ice, the Earth crust lifted and triggered the re-advance of the ice sheet. However, this mechanism is much to slow to prevent dangerous sea-level rise caused by West Antarctica's ice-loss in the present and near future. ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ICE WORLD
NATO says ready to help Italy in Libya

Split families in limbo amid Trump immigration chaos

Pentagon to prepare 20,000 beds for migrant children

US military to help prosecute migrant cases

ICE WORLD
China's Beidou system helps livestock water supply in remote pastoral areas

UK says shut out of EU's Galileo sat-nav contracts

Woman drowns in Prague drains playing GPS treasure hunt

What exclusion from Galileo could mean for UK

ICE WORLD
Key difference between humans and other mammals is skin deep, says study

Improved ape genome assemblies provide new insights into human evolution

Monkeys eat fats and carbs to keep warm

Bonobos won't eat filthy food, offering clues to the origins of disgust

ICE WORLD
EU court rules Malta wild bird traps illegal

Sri Lanka arrests villagers for killing leopard

Dogs recognize, understand human facial expressions

Dozens of last blue macaws to be reintroduced to Brazil

ICE WORLD
Spot a rat? Real-time map aims to plot Paris sightings

US fears of 'mystery weapon' revived by new China diplomat cases

Dialing up the body's defenses against public health threats

Limiting global warming could avoid millions of dengue fever cases

ICE WORLD
Dominican Republic names ambassador to China

China pledges $100 million in military aid to Cambodia

Chinese parents-to-be seek more fertile ground abroad

Nepal PM to seek investment on first official China trip

ICE WORLD
Three Mexican soldiers killed in ambush

US targets Chinese fentanyl 'kingpin' with sanctions

Singaporean guilty of sophisticated exam cheating plot

S. Korea deploys warship to Ghana after pirates kidnap sailors

ICE WORLD








The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.