Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



ICE WORLD
Secrets of hidden ice canyons revealed
by Staff Writers
Paris (ESA) Oct 24, 2017


illustration only

We are all aware that Antarctica's ice shelves are thinning, but recently scientists have also discovered huge canyons cutting through the underbelly of these shelves, potentially making them even more fragile. Thanks to the CryoSat and Sentinel-1 missions, new light is being shed on this hidden world.

Antarctica is surrounded by ice shelves, which are thick bands of ice that extend from the ice sheet and float on the coastal waters. They play an important role in buttressing the ice sheet on land, effectively slowing the sheet's flow as it creeps seaward.

The ice sheet that covers Antarctica is, by its very nature, dynamic and constantly on the move. Recently, however, there has been a worrying number of reports about its floating shelves thinning and even collapsing, allowing the grounded ice inland to flow faster to the ocean and add to sea-level rise.

While scientists continue to study the changing face of Antarctica, monitor cracks in the surface of the ice that might signal the demise of a shelf and learn how these changes are affecting the biology of coastal waters, they are also aware of dramatic changes taking place below the surface, hidden from view.

There are huge inverted canyons in the underside of ice shelves, but little is known about how they form and how they affect the stability of the ice sheet.

One type is thought to be caused by subglacial water that drains from beneath the ice sheet and runs into the ocean. In this region, the ocean water is stratified, with the warmer water at the bottom.

However, as the colder meltwater pours down into the ocean it then rises because it is less dense than the seawater - but as it rises it drags up the warm bottom water which causes the underbelly of the floating ice shelf to melt.

Another type is thought to be caused by the way ocean water circulates under the shelf.

Scientists have been using ESA's CryoSat to study changes in the surface of the ice shelf and the Copernicus Sentinel-1 mission to study how shelves flow to learn more about what's going on hidden from view.

Their focus has been on the Dotson ice shelf in West Antarctica.

Noel Gourmelen from the University of Edinburgh said "We have found subtle changes in both surface elevation data from CryoSat and ice velocity from Sentinel-1 which shows that melting is not uniform, but has centred on a 5 km-wide channel that runs 60 km along the underside of the shelf.

"Unlike most recent observations, we think that the channel under Dotson is eroded by warm water, about 1C, as it circulates under the shelf, stirred clockwise and upward by Earth's rotation.

"Revisiting older satellite data, we think that this melt pattern has been taking place for at least the entire 25 years that Earth observation satellites have been recording changes in Antarctica.

"Over time, the melt has calved in a broad channel-like feature up to 200 m deep and 15 km across that runs the entire length of the underside of Dotson ice shelf.

"We can see that this canyon is deepening by about 7 m a year and that the ice above is heavily crevassed.

"Melt from Dotson ice shelf results in 40 billion tonnes of freshwater being poured into the Southern Ocean every year, and this canyon alone is responsible for the release of four billion tonnes - a significant proportion.

"The strength of an ice shelf depends on how thick it is. Since shelves are already suffering from thinning, these deepening canyons mean that fractures are likely to develop and the grounded ice upstream will flow faster than would be the case otherwise.

"It is the first time that we've been able to see this process in the making and we will now expand our area of interest to the shelves all around Antarctica to see how they are responding. We couldn't do this without CryoSat and the European Commission's Copernicus Sentinel missions," added Dr Gourmelen.

ICE WORLD
Drive for giant new marine sanctuary in Antarctica
Sydney (AFP) Oct 16, 2017
Australia and France kick off a fresh push Monday to create a vast marine sanctuary in pristine East Antarctica, hoping to build on the success of landmark deal secured last year at a key annual conservation summit. The fate of the plan to shield critical areas of ocean around the frozen continent rests with the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), w ... read more

Related Links
CryoSat at ESA
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

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
Plants and psychological well-being in space

Spacewalkers fix robotic arm in time to grab next cargo ship

NASA develops and tests new housing for in-orbit science payloads

Russia's space agency says glitch in manned Soyuz landing

ICE WORLD
NASA awards launch contracts for Landsat 9 and Sentinel-6A

ESA role in Europe's first all-electric telecom satellite

Lockheed Martin Launches Second Cycle of 'Girls' Rocketry Challenge' in Japan

First Four Space Launch System Flight Engines Ready To Rumble

ICE WORLD
Solar eruptions could electrify Martian moons

MAVEN finds Mars has a twisted tail

Mine craft for Mars

Opportunity spends the week imaging Perseverance Valley

ICE WORLD
China launches three satellites

Mars probe to carry 13 types of payload on 2020 mission

UN official commends China's role in space cooperation

China's cargo spacecraft separates from Tiangong-2 space lab

ICE WORLD
Myanmar to launch own satellite system-2 in 2019: vice president

Eutelsat's Airbus-built full electric EUTELSAT 172B satellite reaches geostationary orbit

Turkey, Russia to Enhance Cooperation in the Field of Space Technologies

SpaceX launches 10 satellites for Iridium mobile network

ICE WORLD
The drop that's good to the very end

Study shows how rough microparticles can cause big problems

Selective memory makes data caches 50 percent more efficient

Electrode materials from the microwave oven

ICE WORLD
New NASA study improves search for habitable worlds

From Comets Come Planets

A star that devoured its own planets

Astronomers find potential solution into how planets form

ICE WORLD
Haumea, the most peculiar of Pluto companions, has a ring around it

Ring around a dwarf planet detected

Helicopter test for Jupiter icy moons radar

Solving the Mystery of Pluto's Giant Blades of Ice




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - 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. Privacy Statement