NASA Ice BridgeAirborne campaign over Antarctica to continue critical ice measurementsPosted October 23, 2009
A satellite launched by NASA That means a six-year gap for scientists who use the data collected by the satellite’s laser altimeter system to monitor such things as elevation changes in the ice. Researchers use that information to understand not only how the ice changes over time, but to help calculate the amount of sea level rise from ice lost to the ocean. Follow the Adventure
But NASA has a backup plan to bridge the gap — the largest airborne survey of Earth’s polar ice ever flown. Operation Ice Bridge Seelye Martin “We would be blind without these measurements of the ice sheet and sea ice elevations,” said Martin during a NASA press conference on Oct. 8, a week prior to the first of 17 scheduled flights over the next month. ![]() Photo Credit:
Stefan Elieff/Sander Geophysics
An unusual snowfall on Monday, Oct. 19, grounded the DC-8’s third flight from Punta Arenas, Chile.
“Our motivation in these aircraft observations is based on our concern about contributions of the ice sheets to sea level rise,” Martin said, noting that the Greenland ice sheet in the Arctic is losing 7 percent mass per year. “We do not have a comparable number from Antarctica,” he added. Scientists estimate the West Antarctic Ice Sheet contains enough ice to raise sea levels by about six meters, similar to the Greenland Ice Sheet. The larger, thicker East Antarctica Ice Sheet holds enough ice to increase sea level by an estimated 60 meters. While there is much uncertainty about how high the seas might actually rise by the end of this century, most scientists believe it will be at least half a meter. Many calculate that the true number is two or three times that — enough to flood low-lying areas, from New Orleans to Bangladesh. “Ice Bridge is a really exciting opportunity for us, because NASA satellites have shown us how the ice surfaces are dropping and how the speeds of the ice sheets are increasing and losing mass,” said Robin Bell “The problem with ice sheets is that you can’t see through the ice sheet with satellites,” Bell explained. “Ice Bridge is a unique opportunity to see through the ice and ask the question — really address robustly — why are the ice sheets changing?” In addition to the two precision laser systems, the DC-8 will fly several radars developed by the Center for Remote Sensing of Ice Sheets (CReSIS) The center’s ability to meet NASA’s requirements for Operation Ice Bridge is thanks to prior funding from the NSF and NASA, according to CReSIS scientists. “It is only because of CReSIS we were able to develop advanced radars and antenna structure in a short time,” noted CReSIS director Prasad Gogineni The NSF, which is not directly supporting Operation Ice Bridge, did assist NASA with an environmental assessment of the project. The low-altitude flights, skimming the ice surface at about 450 meters, could have disturbed penguin and seal colonies, according to Polly Penhale, environmental officer for the NSF’s Office of Polar Programs Employing high-tech mapping techniques, the USAP was able to compare NASA’s proposed flight plan against the location of known animal colonies around the Antarctic Peninsula so that the aircraft could fly higher over those areas to avoid any disturbances, said Nate Biletnikoff, Raytheon Polar Services Co. (RPSC) “The USAP did a great job of helping with the data … [it’s a] great story on interagency cooperation in support of environmental stewardship,” Penhale said. Said Tom Wagner, cryosphere program scientist at NASA headquarters in Washington, D.C.: “This worked great. We let NSF know where we wanted to fly, and then worked with Dr. Penhale and her experts on how to arrange the flight lines to avoid flying near rookeries and other sensitive areas. “In many cases, we simply rerouted; in others, we’re flying at high altitudes over the area,” he added. “In addition, all of the air crew was made aware of how to spot uncharted rookeries and avoid them.” About 50 people are involved in the airborne campaign, representing four NASA centers and five universities, according to Martin. The flights by NASA’s DC-8 will focus on particularly sensitive areas, such as Pine Island Bay, where Pine Island Glacier has sped up over the last few years. “Pine Island is a particularly sensitive area because much of the land on which the ice sits is below sea level,” Martin said. “The rate of mass loss from this region is about a meter a year and may be increasing.” This year's airborne campaign is scheduled to be completed by mid-November. |