GPS World

Tag: Greenland

  • Greenland is twisting and stretching, GNSS data shows

    Greenland is twisting and stretching, GNSS data shows

    Greenland is being twisted, compressed and stretched, according to researchers in the Department of Space Research and Space Technology of the Technical University of Denmark (DTU Space). As a result, the entire island has shifted northwest over the past 20 years by about 2 centimeters per year.

    GNSS data shows plate tectonics and movements in the bedrock caused by the melting of large ice sheets, reducing pressure on the subsurface. The pressure is easing both because large amounts of ice have melted in Greenland in recent years, and because the bedrock is still affected by the enormous ice masses that have melted since the peak of the last Ice Age around 20,000 years ago.

    Horizontal land motion observed by the 58 GNET stations used in this study, processed in the IGS14 reference frame. Their location is shown by the colored circles together with their labels. The boundaries of Greenland's drainage basins are shown in green with numbers (1) to (7b). The Greenland Ice Sheet (GrIS) is represented in white and peripheral glaciers in Greenland (GrPG) and Arctic Canada (CanPG) are highlighted in black and purple respectively. (Image: Study authors)
    Horizontal land motion observed by the 58 GNET stations used in this study, processed in the IGS14 reference frame. Their location is shown by the colored circles together with their labels. The boundaries of Greenland’s drainage basins are shown in green with numbers (1) to (7b). The Greenland Ice Sheet (GrIS) is represented in white and peripheral glaciers in Greenland (GrPG) and Arctic Canada (CanPG) are highlighted in black and purple respectively. (Image: Study authors)

    The new measurements are based on 58 GNSS stations placed around Greenland. They measure Greenland’s overall position, elevation changes in the bedrock, and how the island is shrinking and stretching. The movements are causing Greenland to both expand and contract horizontally. The effect is that Greenland’s area is currently being “stretched out” and becoming slightly larger in some regions, while others are being “pulled together.”

    ”Overall, this means Greenland is becoming slightly smaller, but that could change in the future with the accelerating melt we’re seeing now,” said DTU Space postdoc researcher Danjal Longfors Berg, lead author of the article in the Journal of Geophysical Research.

    It is the first time the horizontal movements have been described in such detail.

    ”We have created a model that shows movements over a very long timescale from about 26,000 years ago to the present. At the same time, we have used very precise measurements from the past 20 years, which we use to analyze the current movements. This means we can now measure the movements very accurately,” Berg said.

    Important for surveying and navigation

    The new research provides useful information about what happens when climate change hits the Arctic with accelerating speed, as is the case in these years.

    ”It’s important to understand the movements of landmasses. They are of course interesting for geoscience. But they are also crucial for surveying and navigation, since even the fixed reference points in Greenland are slowly shifting,” Berg said.

    The GNSS stations are owned by the Climate Data Authority under the Ministry of Climate, Energy and Utilities. They are used for research purposes and operated in collaboration with DTU Space. The research is conducted under the DTU Space research center Center for Ice-Sheet and Sea-Level Predictions (CISP).

  • Galileo SAR enhanced with new Greenland site

    Galileo SAR enhanced with new Greenland site

    Image: KimKimsenphot/iStock / Getty Images Plus/Getty Images
    Image: KimKimsenphot/iStock / Getty Images Plus/Getty Images

    The European Union Agency for the Space Programme (EUSPA) and Naviair — a company that specializes in air navigation and related infrastructure services and is owned by the Danish state and represented by the Ministry of Transport — have partnered to strengthen the monitoring capabilities of the Galileo search and rescue (SAR) service by adding a new site in Greenland.

    The partnership between EUSPA and Naviair will expand the ground segment and current SAR capabilities. As part of the agreement, Naviair will contribute to the Galileo Programme objectives by procuring, deploying, hosting, and operating a reference beacon (REFBE) near the Kangerlussuaq Airport in Greenland.

    The new SAR/Galileo site and REFBE will be located around the margins of the declared service coverage area and will be fully integrated into the SAR ground segment, bringing the number of REFBEs to eight. The REFBEs provide data for service performance monitoring.

    There are currently five REFBEs in the European coverage area and two in the Indian Ocean coverage area.

    The REFBEs are fitted with vertical linear polarized antennas that transmit timely, synchronized signals equivalent to a standard 406 MHz Cospas-Sarsat beacon. This, combined with their well-known position, enables specific SAR/Galileo Service performance indicators to be derived.

    The new site will be ready by the fourth quarter of 2023.

    The SAR/Galileo component of the EU Space Programme plays a crucial role in the detection of emergency signals transmitted by distress beacons in support of the internationally recognized SAR Cospas-Sarsat program. As part of this program, the Galileo SAR Service utilizes SAR instruments onboard Galileo satellites, medium-Earth orbit local user terminals, and a network of SAR REFBEs located across Europe.

  • UAV finds WWII plane under Greenland ice

    A team deployed ground-penetrating radar mounted on drones, showing that the technology can search and locate targets buried deep in glacial ice.

    On July 15, 1942, six P-38 Lightning fighter aircraft and two B-17 Flying Fortress bombers encountered a blizzard while supporting the Allied war effort in the British Isles.

    The aircraft were forced to conduct an emergency landing on the glaciers of Greenland, and though all the crew members were rescued nine days later, the aircraft were left behind.

    After using radar to find areas of interest in 2011, an expedition led by the non-profit Arctic Hot Point Solutions returned to Greenland.

    Ground-penetrating radar was integrated with a drone for the survey mission in Greenland. (Photo: Arctic Hotpoint Solutions)
    Ground-penetrating radar was integrated with a drone for the survey mission in Greenland. (Photo: Arctic Hotpoint Solutions)

    This time, the team deployed ground-penetrating radar mounted on drones, and showed that the technology can search and locate targets buried deep in glacial ice. Aerial surveying was more effective and less risky than working on the ice.

    The team extracted hydraulic fluid from 340 feet below the surface, leading to the identification of the buried aircraft as the P-38 Echo piloted by Robert Wilson.

    Six undiscovered aircraft — also part of the “Lost Squadron” — remain entombed in shifting glaciers, along with many additional WWII aircraft that went down over of Greenland as they flew between the United States and the European theater.

    A future expedition will attempt to excavate Echo, and locate other aircraft of the Lost Squadron.

  • Geologist uses lidar to monitor Greenland Glacier ice loss

    A Riegl VZ-6000 laser scanner, operating at 1064 um wavelength, serves as the backbone of the ATLAS system.
    A Riegl VZ-6000 laser scanner, operating at 1064 um wavelength, serves as the backbone of the ATLAS system.

    Leigh Stearns, a geologist with the University of Kansas, is working with a Riegl VZ-6000 ultra long range terrestrial laser scanner, incorporated into an ATLAS (Autonomous Terrestrial Laser Scanning) system, to monitor rates of ice loss on the Helheim Glacier, a tidewater glacier undergoing large-scale changes due to global climate change.

    “Lidar is an emerging technology for the earth sciences because it produces an incredibly detailed 3-D view of features,” said the KU researcher. “Repeat lidar scanning reveals small-scale changes with very high precision. These systems are now used to measure how bridges are sagging, how tectonic faults propagate and now how glaciers flow. The ATLAS systems are unique because they’re designed to scan the glacier terminus every six hours, year-round. That’s not a trivial task when there’s no sunlight in the winter, winds are high and it’s very cold.”

    The VZ-6000 high speed, high-resolution terrestrial 3D laser scanner offers an extremely long measurement range of more than 6000 meters for topographic (static) applications. Due to its laser wavelength, it is exceptionally well suited for measuring snowy and icy terrain in glacier mapping and monitoring applications in mountainous regions.

    Learn more about the project at the University of Kansas website.

  • New GPS study finds 200 gigatons of ice missing

    A new study based on GPS measurements of the Earth’s crust suggests the Greenland ice sheet is melting 7 percent faster than previously believed and may contribute more to future sea level rise than predicted, reports the Canadian Broadcasting Corporation.

    “We’ve underestimated the rate of ice loss by about 7.6 percent,” says Michael Bevis of The Ohio State University, one of the study’s co-authors.

    The research found that Greenland lost close to 2,700 gigatons of ice from 2003–2013, rather than the 2,500 gigatons figure that scientists previously believed. The study, published in the journal Science Advances, is an international effort that started in 2007, with contributions from the U.S., Denmark and Luxembourg.

    Over the past two decades the Greenland ice sheet has been shrinking — partly due to accelerated glacier flow and partly because of surface melt. However, scientists have not been able to pinpoint exactly how much the melting ice sheet is contributing to global sea level rise — information key to making predictions about future sea rise levels.  Part of the challenge has been a lack of on-site data.

    For this study teams of scientists spent years installing GPS devices around the  perimeter of the Greenland ice sheet to collect new data. The team discovered that the hotspot in the Earth’s mantle that feeds Iceland’s active volcanoes has been distorting data.