Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greenland ice sheet still losing mass

25.09.2006
Data gathered by a pair of NASA satellites orbiting Earth show Greenland continued to lose ice mass at a significant rate through April 2006, and that the rate of loss is accelerating, according to a new University of Colorado at Boulder study.

The study indicates that from April 2004 to April 2006, Greenland was shedding ice at about two and one-half times the rate of the previous two-year period, according to CU-Boulder researchers Isabella Velicogna and John Wahr. The researchers used measurements taken with the Gravity Recovery and Climate Experiment, or GRACE, to calculate that Greenland lost roughly 164 cubic miles of ice from April 2004 to April 2006 -- more than the volume of water in Lake Erie.

The new study, published in the Sept. 21 issue of Nature, follows on the heels of a study published in Science in August by a University of Texas at Austin team using GRACE that showed Greenland lost 57 cubic miles of ice annually from 2002 to 2005. The new CU-Boulder study indicates the speed-up in ice mass loss charted by the researchers has been occurring primarily in southern Greenland, said Velicogna.

"The acceleration rate really took off in 2004," said Velicogna, a researcher at the CU-Boulder-based Cooperative Institute for Research in Environmental Sciences. "We think the changes we are seeing are probably a pretty good indicator of the changing climatic conditions in Greenland, particularly in the southern region."

Studies by several research groups indicate temperatures in southern Greenland have risen by about 4.4 degrees F in the past two decades, she said.

The CU-Boulder findings also are consistent with studies charting a dramatic acceleration of the Kangerdlugssaq and Helheim glaciers in southeast Greenland using satellite radar observations, said Wahr. A 2006 study by researchers at the University of Wales, for example, showed the two glaciers have doubled their speed and are dumping twice as much ice into the sea as they did five years ago.

"Our results correlate well with independent observations of glacier acceleration in the south of Greenland," said Wahr, also a professor of physics at CU-Boulder. "It's a fairly straightforward story -- the ice loss in Greenland increased dramatically in 2004, particularly in the south, and it is continuing."

CIRES Director Konrad Steffen, who has maintained more than 20 climate stations in Greenland for nearly two decades, said temperatures have warmed by more than 4 degrees F along the western slope of its ice sheet since 1990. "The increased surface melt of snow and ice provides additional meltwater to lubricate the bottom of the ice sheet and increases the ice flow velocity toward the coast," said Steffen, a CU-Boulder geography professor who was not involved in the Nature study.

Launched in 2002 by NASA and Germany, the two GRACE satellites whip around Earth 16 times a day at an altitude of 310 miles, sensing subtle variations in Earth's mass and gravitational pull. Separated by 137 miles, the satellites measure changes in Earth's gravity field caused by regional changes in the planet's mass, including ice sheets, oceans and water stored in the soil and in underground aquifers.

A change in gravity due to a pass by GRACE over a portion of Greenland imperceptibly tugs the lead satellite away from the trailing satellite, said Velicogna. A sensitive ranging system allows researchers to measure the distance of the two satellites down to as small as 1 micron -- about 1/50 the width of a human hair -- and to then calculate the ice mass in particular regions of Greenland.

In March 2006, Velicogna and Wahr used GRACE to determine that the Antarctic ice sheet -- which holds 70 percent of Earth's freshwater -- lost up to 36 cubic miles of ice annually from April 2002 to August 2005. Greenland, the largest island in the world, harbors about 10 percent of the world's freshwater in its ice sheet, which is up to two miles thick in places. If the Greenland ice sheet melted completely, the world's oceans would rise more than 20 feet, according to scientists.

Significant ice loss in Greenland has the potential to have severe effects on the climate of the Northern Hemisphere, said Velicogna, who also is affiliated with the Jet Propulsion Laboratory in Pasadena, Calif., which manages GRACE for NASA. Scientists believe that large amounts of freshwater purged from Greenland's eastern coast could help to weaken the counterclockwise flow of the North Atlantic Current, lowering water and wind temperatures and potentially triggering abrupt cooling events in northern Europe.

Isabella Velicogna | EurekAlert!
Further information:
http://www.colorado.edu
http://www.csr.utexas.edu/grace/gallery/animations/

More articles from Earth Sciences:

nachricht Impacts of mass coral die-off on Indian Ocean reefs revealed
21.02.2017 | University of Exeter

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>