image: Crevasses in the MacAyeal Ice Stream (formerly Ice Stream E) on Antarctica's Siple Coast east of the Ross Ice Shelf captured by the Digital Mapping System camera aboard NASA's P-3 airborne laboratory on a Nov. 26, 2013, IceBridge research flight.
IceBridge researchers returned to their task of data collection after a four-day-long stretch on the ground due to weather cancellations and McMurdo Station's observed Thanksgiving holiday. With the return of good weather on Nov. 26, the P-3B research aircraft took off for a survey of ice streams along the Siple Coast east of the Ross Ice Shelf.
On Nov. 21, the IceBridge team closed out a successful day of surveying sea ice in the Ross Sea with their usual evening meeting and weather briefing. The forecast released just before the meeting showed less-than-promising conditions for the next few days with a low pressure system expected to move into the McMurdo area in the afternoon, bringing high winds. The next morning, IceBridge mission planners decided the risk of returning to McMurdo to face strong crosswinds and blowing snow was too high and canceled the day's flight.
The next possible day to fly was Monday, Nov. 25, as the McMurdo airfield was closed for the weekend's Thanksgiving events. Early in the morning, IceBridge mission planners did their daily check with the McMurdo weather office to find more high winds in the forecast and called off that day's flight. Later in the day at the evening team meeting, the weather outlook showed promise for the next day.
The morning of Nov. 26, the news from the weather office showed poor conditions over the Ross Sea, eliminating any sea ice flight choices, and clouds over parts of the Antarctic Plateau that would block instruments there. With this information in hand, mission planners decided to fly across the Ross Ice Shelf to survey ice streams -- portions of the ice sheet that move faster than surrounding ice -- moving from the Siple Doam into the ice shelf, a region known as the Siple Coast.
After takeoff and a pass between White and Black Islands near McMurdo, the P-3 crossed the Ross Ice Shelf and turned to follow a track last measured by NASA's Ice, Cloud and Land Elevation satellite, or ICESat. Satellite ice velocity measurements show these ice streams speeding up, but less is known about how their elevation has changed since ICESat stopped functioning in 2009. "Today's data are an important data point in a long time-series of elevation change," said Michael Studinger, IceBridge project scientist.
IceBridge is looking at a couple more flight opportunities before the P-3 is scheduled to leave Antarctica followed a few days later by the rest of the team on Dec. 2. More info: www.nasa.gov/icebridge
Credit: NASA