Some spectacular scenery was in view from NASA's DC-8 flying laboratory as it flew a low-level data collection flight over George VI Sound on the Antarctic Peninsula on Nov. 16. (NASA / Chris Miller) › View Larger Image
New Targets Surveyed as IceBridge Nears Conclusion
Scientists aboard NASA's DC-8 flying laboratory were busy capturing data on glacial movement and ice thickness as the Fall 2011 Operation IceBridge campaign over Antarctica neared its conclusion.
During six long-duration flights over the past week from its deployment base in Punta Arenas, Chile, the converted jetliner and its complement of scientists and flight crew surveyed several new targets over the frozen continent as well as repeating precise flight tracks over targets surveyed on prior missions. By comparing data recorded during the current campaign with that from previous IceBridge flights, scientists hope to improve their understanding of why the ice sheets are thinning and the potential effect of that on sea level rise.
On Wednesday, Nov. 9, the team made its longest flight of the mission to date, a 12.5-hour flight to the Thwaites Glacier and eastern Byrd Land, including overflights of ice core sample locations. The seven unique science instruments aboard the aircraft recorded measurements of sea ice and glacial thickness while the DC-8 maintained an altitude of only 1,500 feet above ground level during more than five hours of data collection. This flight also reached the most southerly point of any of the IceBridge flights, just less than 80 degrees south latitude.
"Upon reaching the Amundsen Sea, the weather was not at all promising, but after a short time, it cleared up and conditions remained favorable for the rest of the day," reported pilot-in-command Troy Asher of NASA's Dryden Flight Research Center. "The research area was like Kansas in Antarctica, flat for as far as the eye could see in all directions."
After a delayed takeoff to allow weather over the target area to clear, the flying laboratory was back in the air Nov. 11 for a low-level return flight over the Thwaites Glacier. As a bonus, a leg was flown over the now-famous Pine Island Rift at 10,000 feet altitude to allow for data collection by the Airborne Topographic Mapper.
"The view was spectacular of both the rift and glacier edge under sunny skies," reported NASA Dryden mission manager Chris Miller, noting that predictions for full separation of the ice mass from the main glacier range from a few weeks to months.
The first of two flights over the weekend of Nov. 12-13 saw the aircraft once again over the Thwaites and Pine Island Glaciers, an 11.6-hour flight that included almost six hours of data collection by the seven specialized instruments. Clear skies allowed scientists and flight crew to cover all of the planned data collection lines from 1,500-feet altitude, including detailed mapping of the Pine Island rift.
An 11.2-hour flight Nov. 13 took the four-engine aircraft the IceBridge team over the Crosson Ice Shelf, with some of the data collection flight tracks extending over the Thwaites and Dotson ice shelves and over Mt. Murphy in between.
"Data lines were purposely designed to overfly areas of exposed bedrock to better constrain the measurements from the Gravimeter instrument," Miller reported, adding that the team was rewarded with spectacular views of the mountain.
On Monday, Nov. 14, the IceBridge science team had a rare opportunity to collect data over glaciers on the east side of the northern Antarctic Peninsula that are normally enshrouded in clouds. Six of the seven instruments recorded measurements during 5 ½ hours of data collection.
After a "hard down" no-flying day Nov. 15, the team was again aloft on Wednesday Nov. 16 for an 11.9-hour mission over the Antarctic Peninsula Elbow. During 7.1 hours of science data collection, the flying laboratory followed the track of prior-year IceBridge missions. Starting from the southwest of the peninsula, the flight track led east along the English Coast and north along the eastern shore of George VI Sound, cresting several mountain ranges.
"The track took us up and over several mountain ranges, treating us to astonishingly close views of jagged rock and precipitous snow banks," Miller recalled. "The pilot was following very precisely a pre-planned flight path first laid down by a P3 a number of years ago."
After a final weekend of data collection flights, the DC-8 and the IceBridge team are scheduled to return home Nov. 22 to the airborne science laboratory's base at the Dryden Aircraft Operations Facility in Palmdale, Calif. A Gulfstream-V operated by the National Science Foundation and the National Center for Atmospheric Research that also participated in the 2011 Antarctic IceBridge mission returned to the United States in early November.
Now in its third year, Operation IceBridge began in 2009 using a suite of specialized instruments to collect data about the thickness of Arctic and Antarctic ice on both sea and land and glacial movement to enhance scientists' understanding and predictions of how glaciers contribute to global sea level rise.
› Learn more