The ice stream of Recovery Glacier distinguishes itself from slower-moving ice by its shredded, rough appearance. (Photo courtesy Christopher Shuman/NASA/UMBC/JCET) › View Larger Image
Missions Following Up on Discoveries
With only about 20 percent of planned mission flight hours remaining, long-duration data collection flights by NASA's DC-8 airborne science laboratory are continuing over the ice shelves and glaciers of Antarctica in the fall 2011 Operation IceBridge campaign.
After follow-up missions over the Pine Island Glacier, where scientists aboard the DC-8 discovered a huge, 18-mile-long crevasse that is leading to calving of a massive iceberg in the near future, the IceBridge team turned its attention to the Getz Ice Shelf southwest of the Antarctic Peninsula, the Thwaites and Recovery glaciers and several other targets during flights made Nov. 3-7.
A 11.7-hour flight from the deployment base in Punta Arenas, Chile, Nov. 3 included about 5.5 hours of low-altitude data collection with the seven specialized instruments aboard the converted jetliner, primarily over the Thwaites Iceberg Tongue, the Dodson Ice Shelf and Peter the First Island.
Another flight of the same duration the following day was described by Dryden mission manager Chris Miller as "mowing the lawn" - his description of flying nine parallel flight tracks at only 1,500 feet altitude over the Thwaites Glacier. Although visibility was poor for the first few tracks due to low clouds, it improved significantly to reveal a deeply fissured landscape of blue and white ice with 300-foot-deep crevasses with "spectacular broken and tumbled ice near the edge of the shelf," Miller wrote. He noted that all of the instruments functioned well, and good data were collected.
After inclement weather over the target areas forced postponement of a flight scheduled for Nov. 5 and 6, the team was back in the air Nov. 7, collecting data for more than three hours over the Recovery Glacier southeast of the Antarctic Peninsula region during a 12-hour flight. The mission included an overflight of the Shackleton Range, the Slessor Glacier, the Bailey Ice Steam and several suspected submerged lakes.
"This was the only area of all our remaining targets where the weather was good enough to fly," reported Dryden's senior pilot Dick Ewers, noting that clear weather at the Recovery Glacier allowed for 100 percent data collection on each ground track. After completing all data tracks, the return course then included extending the final course line to allow data to be collected at the glacier ground line.
After a day off Nov. 8 for crew rest, aircraft and instrument maintenance, the flying laboratory has been back in the air for six missions. About 46 hours of the planned 250 Operation IceBridge flight hours remained as of Nov. 10, including the long transit flight back to the DC-8's home base at the Dryden Aircraft Operations Facility in Palmdale, currently slated for Nov. 22.
Work with a Gulfstream V, which was operated by the National Science Foundation and the National Center for Atmospheric Research and used in the 2011 Antarctic IceBridge mission, has been completed and that aircraft has returned to the United States.
Now in the third year, Operation IceBridge began in 2009. The campaign is being conducted 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 of how glaciers contribute to global sea-level rise.