. 24/7 Space News .
ICE WORLD
Snow over Antarctica buffered sea level rise during last century
by Maria-Jose Vinas for GSFC News
Greenbelt MD (SPX) Dec 14, 2018

A new NASA-led study has determined that an increase in snowfall accumulation over Antarctica during the 20th century mitigated sea level rise by 0.4 inches. However, Antarctica's additional ice mass gained from snowfall only makes up for about a third of its current ice loss. These findings don't necessarily mean that Antarctica is growing; it's still losing mass, even with the extra snowfall. However, without these gains, the planet would have experienced even more sea level rise in the 20th century. The polar ice sheets grow via snow accumulation and shrink through melting and the production of icebergs. Presently, both ice sheets are imbalanced -losing more ice annually than they are gaining- and their ice loss is estimated to be currently causing about a half of the observed sea level rise.

A new NASA-led study has determined that an increase in snowfall accumulation over Antarctica during the 20th century mitigated sea level rise by 0.4 inches. However, Antarctica's additional ice mass gained from snowfall makes up for just about a third of its current ice loss.

"Our findings don't mean that Antarctica is growing; it's still losing mass, even with the extra snowfall," said Brooke Medley, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, which was published in Nature Climate Change on Dec. 10. "What it means, however, is that without these gains, we would have experienced even more sea level rise in the 20th century."

The polar ice sheets grow via snow accumulation and shrink through melting and the production of icebergs. Presently, both ice sheets are imbalanced -losing more ice annually than they are gaining- and their ice loss is estimated to be currently causing about a half of the observed sea level rise. Sea level adjusts to changes in snowfall, which modulates how much water is locked into the ice sheets.

Snowfall is very difficult to measure over Antarctica. For starters, there are very few weather stations in the frozen continent, and most of them are installed along the coastline. Secondly, satellites have a hard time measuring snow from space - they basically confuse the snow that's falling down with the snow that's already on the ground.

Climate models struggle to replicate the total amount of snow that falls over Antarctica each year. So scientists often have to rely on ice cores, cylinders of ice drilled from the ice sheet whose layers store a trove of information; amongst it, how much snow fell in a certain year or decade. But drilling ice cores is logistically challenging, so they are sparse and do not cover the entire continent.

Medley and her colleague, British Antarctic Survey's Elizabeth Thomas, reconstructed how much snow fell over the entire Antarctic continent and nearby islands from 1801 to 2000 using 53 ice cores and three atmospheric reanalyses -climate models informed by satellite observations. Ice cores are only point measurements of snow accumulation, but by comparing them to the reanalyses' simulations of Antarctic snowfall across the ice sheet, the researchers were able to determine the area of Antarctica each ice core was representative of.

The scientists found that the distribution of ice cores gave a good coverage of most of Antarctica, with some gaps in portions of East Antarctica due to the fact that this area of the continent sees extremely little snowfall, making it difficult to measure.

"Antarctica is bigger than the contiguous United States. You wouldn't say that because you're in New York City and it's snowing, it must mean that it's also snowing in San Diego. It's the same with Antarctica; you can't just stand in one spot, take one measurement and say 'okay, I think I have a good handle on all of Antarctica.' It requires a lot of measurements," Medley said.

Medley and Thomas found that snow accumulation increased over the 20th century by 0.04 inches per decade, and that rate more than doubled after 1979.

"From the ice cores we know that the current rate of change in snowfall is unusual in the context of the past 200 years," Thomas said.

The researchers also investigated what caused the increase of snowfall and its distribution pattern over the ice sheet from 1901 to 2000. They found that it was consistent with a warming atmosphere, which holds more moisture, combined with changes in the Antarctic circumpolar westerly winds that are related to the ozone hole. A related paper published in Geophysical Research Letters on Dec. 10 confirms the relationship between stratospheric ozone depletion and increased snowfall over Antarctica.

"The fact that changes in westerly winds due to ozone depletion plays a role in Antarctic snow accumulation variability indicates that even this remote, uninhabited land has been affected by human activity," Medley said.

"The increased snowfall is a symptom of the same changes in atmospheric circulation that are causing the melt of Antarctic ice," Thomas said.

"Snowfall plays a critical role in Antarctic mass balance and it will continue to do so in the future," Medley said. "Currently it is helping mitigate ice losses, but it's not entirely compensating for them. We expect snowfall will continue to increase into the 21st century and beyond, but our results show that future increases in snowfall cannot keep pace with oceanic-driven ice losses in Antarctica."

Medley hoped that their results will also help evaluate existing climate models so that ice sheet modelers can pick the most reliable ones to use for their predictions of how the Antarctic ice sheet will behave in the future.


Related Links
ICESat-2 at NASA
Beyond the Ice Age


Thanks for being there;
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 Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


ICE WORLD
The fauna in the Antarctica is threatened by pathogens humans spread in polar latitudes
Barcelona. Spain (SPX) Dec 11, 2018
The new study, which detected bacteria from humans in the genus Salmonella and Campylobacter in Antarctic and Subantarctic marine birds, reveals the fragility of polar ecosystems and warns about the risk of massive deaths and extinctions of local fauna populations due pathogens. Explorers, whalers, scientists -and lately, tourists-, are examples of human collectives that moved to the furthest regions of the planet. Some studies have claimed for years that there had been cases of reverse zoonosis, ... 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
Four NASA-sponsored experiments set to launch on Virgin Galactic spacecraft

Virgin Galactic reaches edge of space in historic flight

Virgin Galactic's SpaceShipTwo reaches space for first time

No drill traces detected on photos of damaged Soyuz protection plates

ICE WORLD
Roscosmos to submit super-heavy rocket project to Government

Aerojet Rocketdyne awarded DARPA contract to design advanced opfires propulsion system

NASA Sounding Rockets Carry TRICE-2 over Norwegian Sea

Tesla CEO Elon Musk taunts US financial regulatory agency

ICE WORLD
NASA's InSight takes its first selfie

Planetary scientists assist in capturing image of Insight from orbit

InSight's robotic arm ready for some lifting on Mars

NASA's InSight lander 'hears' wind on Mars

ICE WORLD
China's Chang'e-4 probe enters lunar orbit

China launches rover for first far side of the moon landing

Evolving Chinese Space Ecosystem To Foster Innovative Environment

China sends 5 satellites into orbit via single rocket

ICE WORLD
CAT rules in favour of Ofcom's EAN authorisation decision

Fleet Space Technologies' Centauri launched aboard SpaceX Falcon 9

Roscosmos Targeted by Info Attack to Hamper Revival of Space Industry in Russia

SAS Signs Distribution Agreement with GlobalSat Group

ICE WORLD
Radiation experiment flies on record-setting SpaceX launch dedicated entirely to small satellites

Astroscale enters technical cooperation with European Space Agency

Deep-learning technique reveals 'invisible' objects in the dark

Researchers develop mathematical solver for analog computers

ICE WORLD
Hubble finds faraway planet vanishing at record speed

Common ground discovered in planet-forming disks

UNLV study unlocks clues to how planets form

The epoch of planet formation, times twenty

ICE WORLD
NASA's Juno mission halfway to Jupiter science

Record Setting Course-Correction Puts New Horizons on Track to Kuiper Belt Flyby

Radio JOVE From NASA: Tuning In to Your Local Celestial Radio Show

The PI's Perspective: Share the News - The Farthest Exploration of Worlds in History is Beginning









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.