The ice stream of Recovery Glacier distinguishes itself from slower-moving ice by its shredded, rough appearance. (Christopher Shuman/NASA/UMBC/JCET)
IceBridge Targets Thwaites, Recovery Glaciers
With only about 20 percent of its planned mission flight hours remaining, NASA's DC-8 airborne science laboratory is continuing long-duration data collection flights 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 could lead to calving of a massive iceberg in the near future, the IceBridge team turned their attention to the Getz Ice Shelf southwest of the Antarctic Peninsula, the Thwaites and Recovery glaciers and several other targets during flights on Nov. 3 through Nov. 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 by 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 mission manager Chris Miller from NASA's Dryden Flight Research Center 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, visibility 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 was collected.
After inclement weather over the target areas forced postponement of the 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 then the return course 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 was scheduled to be back in the air Nov. 9. About 46 hours of the planned 250 Operation IceBridge flight hours remain as of Wednesday morning, including the long transit flight back to the DC-8's home base at the Dryden Aircraft Operations Facility in Palmdale, Calif., currently slated for Nov. 22.
A Gulfstream-V operated by the National Science Foundation and the National Center for Atmospheric Research that was participating in the 2011 Antarctic IceBridge mission has completed its work and has returned to the United States.
Now in the 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.
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