Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA Data Sheds New Light on Changing Greenland Ice

11.03.2014

Research using NASA data is giving new insight into one of the processes causing Greenland's ice sheet to lose mass.

A team of scientists used satellite observations and ice thickness measurements gathered by NASA's Operation IceBridge to calculate the rate at which ice flows through Greenland's glaciers into the ocean. The findings of this research give a clearer picture of how glacier flow affects the Greenland Ice Sheet and shows that this dynamic process is dominated by a small number of glaciers.


The calving front of Greenland’s Jakobshavn Glacier seen during an IceBridge survey flight in 2012.

Image Credit: NASA / Jefferson Beck

Over the past few years, Operation IceBridge measured the thickness of many of Greenland's glaciers, which allowed researchers to make a more accurate calculation of ice discharge rates. In a new study published in the journal Geophysical Research Letters, researchers calculated ice discharge rates for 178 Greenland glaciers more than one kilometer (0.62 miles) wide.

Ice sheets grow when snow accumulates and is compacted into ice. They lose mass when ice and snow at the surface melts and runs off and when glaciers at the coast discharge ice into the ocean. The difference between yearly snowfall on an ice sheet and the sum of melting and discharge is called a mass budget. When these factors are equal, the mass budget is balanced, but for years the Greenland Ice Sheet has had a negative mass budget, meaning the ice sheet is losing mass overall.

For years the processes of surface melt and glacier discharge were roughly equal in size, but around 2006 surface melt increased and now exceeds iceberg production. In recent years, computer model projections have shown an increasing dominance of surface melt, but a limited amount of glacier thickness data made pinpointing a figure for ice discharge difficult.

Ice discharge is controlled by three major factors: ice thickness, glacier valley shape and ice velocity. Researchers used data from IceBridge's ice-penetrating radar – the Multichannel Coherent Radar Depth Sounder, or MCoRDS, which is operated by the Center for Remote Sensing of Ice Sheets at the University of Kansas, Lawrence, Kan. – to determine ice thickness and sub-glacial terrain, and images from satellite sources such as Landsat and Terra to calculate velocity. The team used several years of observations to ensure accuracy. "Glacier discharge may vary considerably between years," said Ellyn Enderlin, glaciologist at the University of Maine, Orono, Maine and the study's lead author. "Annual changes in speed and thickness must be taken into account."

Being able to study Greenland in such a large and detailed scale is one of IceBridge's strengths. "IceBridge has collected so much data on elevation and thickness that we can now do analysis down to the individual glacier level and do it for the entire ice sheet," said Michael Studinger, IceBridge project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "We can now quantify contributions from the different processes that contribute to ice loss."

With data on glacier size, shape and speed, researchers could calculate each glacier's contribution to Greenland's mass loss and the total volume of ice being discharged from the Greenland Ice Sheet. Of the 178 glaciers studied, 15 accounted for more than three-quarters of ice discharged since 2000, and four accounted for roughly half. Considering the large size of some of Greenland's glacier basins, such as the areas drained by the Jakobshavn, Helheim and Kangerdlugssuaq glaciers, this was not exactly surprising.

What they also found was that the size of these basins did not necessarily correlate with glacier discharge rate, shuffling the order of Greenland's largest glaciers. Previously Helheim Glacier was thought to be Greenland's third largest glacier, but this study puts it in fifth place and adds two southeast Greenland glaciers, Koge Bugt and Ikertivaq South to the list of big ice-movers.

Glacier thickness measurements and this study's calculation methods have the potential to improve future computer model projections of the Greenland Ice Sheet. And with a new picture of which glaciers contribute most to mass loss, IceBridge will be able to more effectively target areas in future campaigns, promising more and better data to add to the research community's body of knowledge.

For more information on NASA's Operation Ice Bridge, visit:

www.nasa.gov/icebridge

George Hale
NASA's Goddard Space Flight Center, Greenbelt, Md.

George Hale | EurekAlert!
Further information:
http://www.nasa.gov
http://www.nasa.gov/content/goddard/nasa-data-sheds-new-light-on-changing-greenland-ice/#.Ux4mWYVduac

Further reports about: Flight Glacier Greenbelt Greenland IceBridge NASA Space glaciers measurements observations processes

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>