› View larger Near-vertical peaks and pinnacles often rose higher than NASA's DC-8 flying laboratory during low-level data-gathering flights in the Operation IceBridge campaign. Many of the flight tracks were flown at an average of only 1,500 feet above ground. Credit: NASA / Chris Miller NASA's DC-8 airborne science laboratory has completed its Antarctic 2011 Operation IceBridge science flights and arrived home at its base in Palmdale, Calif., Nov. 22. The IceBridge flight and science team flew a record 24 science flights during the six-week campaign, recording data from a suite of sophisticated instruments on the thickness and depth of Antarctic ice sheets and glacial movement.
The aircraft departed its deployment base at Punta Arenas, Chile, Tuesday morning Nov. 22 and after a refueling stop in Santiago, Chile, set course for Los Angeles International Airport for customs clearance. The flying lab continued on to the Dryden Aircraft Operations Facility in Palmdale, arriving about 8:30 p.m. that evening after almost 15 hours in the air.
A highlight of the IceBridge mission was the discovery during a low-level overflight Oct. 14 of a large crack that had recently begun across the Pine Island Glacier ice shelf, a precursor to the separation of an estimated 310-square-mile iceberg into the ocean in the near future. The growth of the estimated 18-mile-long rift was documented on several subsequent flights.
NASA Airborne Mission Maps Remote, Deteriorating Glaciers
› View larger A close-up image of the crack spreading across the ice shelf of Pine Island Glacier shows the details of the boulder-like blocks of ice that fell into the rift when it split. For most of the 18-mile stretch of the crack that NASA’s DC-8 flew over on Oct. 26, 2011, it stretched about 240 feet wide, as roughly seen here. The deepest points ranged from about 165 to 190 feet, roughly equal to the top of the ice shelf down to sea level. Scientists expect the crack to propagate and the ice shelf to calve an iceberg of more than 300 square miles in the coming months. This image was captured by the Digital Mapping System (DMS) aboard the DC-8. Credit: NASA/DMS NASA's airborne expedition over Antarctica this October and November has measured the change in glaciers vital to sea level rise projections and mapped others rarely traversed by humans.
Operation IceBridge, nearing completion of its third year, is the largest airborne campaign ever flown over the world's polar regions. Bridging a gap between two ice elevation mapping satellites, and breaking new scientific ground on its own, IceBridge this fall has charted the continued rapid acceleration and mass loss of Pine Island Glacier.
IceBridge has now generated three years of laser altimetry data over certain locations to continue the record from NASA's Ice Climate and Elevation Satellite (ICESat), which stopped operating in 2009. IceBridge measurements show Pine Island following its rapid deterioration that began around 2006. Combined IceBridge and ICESat data show the glacier is losing more than six times as much mass per year -- mass loss was measured at 7 gigatons a year in 2005 and about 46 gigatons a year in 2010 – making it one of the most significant climate change response trends that scientists see worldwide. For comparison, the Chesapeake Bay holds about 70 gigatons of water.
› View larger NASA's DC-8 flew over the Pine Island Glacier Ice Shelf on Oct. 14, 2011 as part of the agency's Operation IceBridge. A large, long-running crack was plainly visible across the ice shelf. The DC-8 took off on Oct. 26, 2011, to collect more data on the ice shelf and the crack. The area beyond the crack that could calve in the coming months covers about 310 square miles (800 square kilometers), IceBridge project scientist Michael Studinger said. Credit: NASA/Michael Studinger › View associated video After discovering an emerging crack that cuts across the floating ice shelf of Pine Island Glacier in Antarctica, NASA's Operation IceBridge has flown a follow-up mission and made the first-ever detailed airborne measurements of a major iceberg calving in progress.
NASA's Operation Ice Bridge, the largest airborne survey of Earth's polar ice ever flown, is in the midst of its third field campaign from Punta Arenas, Chile. The six-year mission will yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice.
Pine Island Glacier last calved a significant iceberg in 2001, and some scientists have speculated recently that it was primed to calve again. But until an Oct. 14 IceBridge flight of NASA's DC-8, no one had seen any evidence of the ice shelf beginning to break apart. Since then, a more detailed look back at satellite imagery seems to show the first signs of the crack in early October.
› View larger The landscape of Alexander Island, Antarctica, as seen by NASA's DC-8 on Oct. 24, 2011. Credit: NASA/Michael Studinger Relatively good weather conditions allowed scientists aboard NASA's DC-8 flying laboratory to survey a number of sites in Antarctica during a trio of productive long-duration science flights Oct. 21-24 as the Fall 2011 Operation IceBridge campaign continued.
Meanwhile, scientists aboard the smaller Gulfstream V aircraft operated by the National Science Foundation and the National Center for Atmospheric Research that is also participating in the IceBridge mission have been busy as well, collecting data with the Laser Vegetation Imaging Sensor, or LVIS, a laser-ranging topography mapper. Both aircraft are staging their flights from Punta Arenas, Chile, requiring long transit times to reach the areas targeted for the land and sea ice surveys..
With cooperative weather conditions Oct. 21, the DC-8 completed more than three hours of data collection over the Slosser 1 glacier south of the Weddell Sea area during an 11-hour flight. Mission managers reported scientists were able to achieve 100 percent of their data collection goals for the flight, including gauging glacial thickness and movement over the Shackleton and Theron mountain ranges.
› View larger The Digital Mapping System (DMS) aboard NASA’s DC-8 captured this image of the Getz Ice Shelf in Antarctica on Monday, Oct. 17, 2011. The step down from the ice shelf to sea ice is about 150 feet. Credit: NASA/DMS Operation IceBridge is all about ice, as the name implies, but one of the more intriguing series of measurements the mission has been making are those of the bathymetry under ice shelves. Bathymetry is the measurement of the depth and contours of lake or ocean floors. It's important in Antarctica because the shape of the ocean floor determines the movement of currents. The movement of currents and the temperature of the water in those currents can play an important role in the interaction between floating ice shelves and the land they are attached to. Warmer ocean water can accelerate the melting of a glacier at its grounding line – the underwater point where the ice shelf connects with the land.
IceBridge is making these ocean floor measurements with an instrument called a gravimeter, operated by Columbia University aboard NASA's DC-8. The gravimeter measures subtle shifts in Earth's gravity field that scientists can use to interpret the shape of the seafloor beneath ice shelves.
The DC-8 flew to the Getz Ice Shelf on Monday, Oct. 17, with a twofold purpose of continuing seafloor measurements below the Getz shelf and to continue mapping the ice surface and bedrock upstream of the grounding line. The flight recovered territory measured in the 2009 and 2010 Antarctica campaigns – a point that highlights IceBridge's central purpose to make repeated measurements over time to gauge how much the continent's ice is changing and to determine what is causing the change.
NASA Continues Critical Survey of Antarctica's Changing Ice
› View larger NASA’s Operation IceBridge mission comprises the largest airborne research campaign ever flown over Earth’s polar region. The mission is designed to continue critical ice sheet measurements in a period between active satellite missions and help scientists understand how much the major ice sheets of Greenland and Antarctica could contribute to sea level rise. Credit: NASA/Michael Studinger Scientists with NASA's Operation IceBridge airborne research campaign began the mission's third year of surveys this week over the changing ice of Antarctica.
Researchers are flying a suite of scientific instruments on two planes from a base of operations in Punta Arenas, Chile: a DC-8 operated by NASA and a Gulfstream V (G-V) operated by the National Science Foundation and the National Center for Atmospheric Research. The G-V will fly through early November. The DC-8, which completed its first science flight Oct. 12, will fly through mid-November.
Ninety-eight percent of Antarctica is covered in ice. Scientists are concerned about how quickly key features are thinning, such as Pine Island Glacier, which rests on bedrock below sea level. Better understanding this type of change is crucial to projecting impacts like sea-level rise.
› View Larger The NSF/NCAR G-V takes off from Punta Arenas, Chile on its fourth IceBridge science flight. Credit: NASA While NASA's venerable DC-8 took off from Punta Arenas this morning for its first science flight of the Antarctica 2011 Operation IceBridge campaign, a much smaller plane that flies at a much higher altitude made its fourth flight in six days. A Gulfstream-V (G-V) operated by the National Science Foundation and National Center for Atmospheric Research is making its IceBridge debut this campaign, but it is carrying an instrument that has been part of the campaign from the beginning: LVIS, the Land, Vegetation and Ice Sensor. LVIS, pronounced like "Elvis," has found a good home on the G-V, which has been stripped down to a bare-bones interior to make room for scientific instruments and team members. The G-V will fly at about 45,000 feet in order to optimize LVIS' ability to create finely detailed ice sheet elevation data and topography maps of key Antarctic glaciers. LVIS is a scanning laser altimeter. As the instrument scans a 2-kilometer-wide swath it pulses 100 beams of laser light and measures how the light scatters to create topographical maps. This kind of data rounds out scientists' understanding of how glaciers and ice sheets change and move over time.
The LVIS team's first four flights have covered previous ICESat track lines along the Antarctic Peninsula and over Pope, Thwaites and Pine Island Glaciers and made a trip today to the Evans Ice Stream. With gridded elevation and topography data over scientifically significant regions – such as Thwaites and Pine Island glaciers, because of their size and their speed – helps scientists get a more detailed picture of ice changes in Antarctica. Ultimately, understanding how quickly ice sheet changes are happening and what is driving them is the key goal of IceBridge's effort to better project future sea-level rise.
IceBridge Instrument Integration on NASA's DC-8
› View Larger Crews work integrating instruments on NASA's DC-8 in preparation of the next leg of Operation IceBridge - Antarctica. Credit: NASA Airborne Science/Emily Schaller With a schedule of flights over Antarctica soon approaching, crews started work this week integrating instruments onto the two planes that will carry out the next leg of Operation IceBridge. The flights will put a variety of laser-ranging, radar and gravity-measuring instruments over Antarctica's ice sheets, glaciers sea ice and surrounding ocean waters for the third consecutive year. IceBridge was designed to bridge the gap between crucial data supplied from space by ICESat-1, which stopped operating in 2009, and ICESat-2, scheduled for launch in 2016. IceBridge flights are planned out to go over specific satellite tracks ICESat-1 covered, specific flight lines from previous IceBridge campaigns and to take new measurements entirely. This collection of data over time and space will be critical to scientists' understanding climate change's impact on polar regions and the impact of ice changes on sea level rise and global climate.
This 2011 Antarctic IceBridge campaign will feature the return of NASA's DC-8, at 157 feet long the largest plane in the agency's airborne research fleet and will feature the debut of the Gulfstream V (G-V) operated by the National Science Foundation and National Center for Atmospheric Research. The DC-8 will fly radars to measure snow depth on top of ice and the solid terrain under the continent's massive ice sheets, a laser instrument to map ice sheet topography and a gravimeter to measure seawater-filled cavities near where glaciers meet the sea. A crew started integrating the instruments on the DC-8 this week at NASA's Dryden Flight Research Center near Palmdale, Cal., the DC-8's home base. Because of instrument requirements, the DC-8 will fly as low as 1,500 feet above Antarctica. Meanwhile, the G-V will fly at altitudes higher than 30,000 feet, optimizing the use of what will be the sole instrument on board – the Land, Vegetation and Ice Sensor (LVIS), which makes detailed topographic studies of the surface.
Punta Arenas, Chile will once again be home to the base of operations for this in-the-field portion of the IceBridge mission. The G-V will make research flights between Oct. 5 and Nov. 2, while the DC-8 will fly between Oct. 12 and Nov. 19. Let the science begin.