Punta Arenas, Chile A team of Kansas University researchers is in the midst of playing a special role in monitoring the health of the planet. It began with “mowing the lawn.”
In a jet. Over Antarctica.
Stationed for six weeks in Chile, electrical engineering professor Chris Allen and several graduate research assistants from the National Science Foundation’s Center for Remote Sensing of Ice Sheets at KU are taking long flights over Antarctica for NASA’s Operation ICE Bridge.
As a NASA satellite that monitors climate fails, this mission provides information about the world’s polar ice by flying various scientific instruments until a new satellite is launched in 2014.
“Probably the greatest uncertainty right now on ice sheet models is the shape of the bed. That’s why the radar work that CReSIS is doing is so important,” says Tom Wagner, NASA’s cryosphere program manager. “CReSIS is widely recognized as one of the leaders in ice sheet radar work. They currently have the most sophisticated radars.”
This part of the mission, which ends Nov. 24, includes 17 strategically plotted flights over Antarctica. Each path — whether “mowing the lawn,” or flying an arc along
-86° latitude — was selected for the new information it provides or to replicate the path of the dying satellite.
The KU team brings an engineer’s detached interest and passion for the craft to the mission. Members are focused on the radar gizmos they made back home in Kansas.
“I would put them in the class of pioneering instruments, giving the scientists new capability,” Allen says. “The MCoRDS — Multi-channel Coherent Radar Depth Sounder — allows us to measure the thickness of the ice. It’s the only instrument on the plane that allows us to measure, directly, the thickness of the ice.”
The two other KU radars — altimeters — will tell scientists the thickness of the snow on the ice sheets, data that Allen says scientists have long wanted.
“That’s really important because that’s one of the biggest unknowns, is how much is accumulating on top of them,” Wagner says from his Washington, D.C., office. “It changes the elevation.”
More snow means ice sheets may not be as robust as originally thought.
Flight days begin early with a quick breakfast at the headquarters hotel in Punta Arenas. Nearly 40 people grab coats and gear before heading to the airport 10 miles outside the city.
Bill Brockett, chief pilot for NASA’s DC-8 flying laboratory, leads the preflight briefing for crew and passengers. There’s a review of the 11-hour flight plan and an overview of the day’s objective — a high-altitude pass over Pine Island Glacier.
“If you’ve ever had the pleasure of hand mowing about two acres of lawn, this is what we’re going to be doing today,” Brockett adds. “Back and forth in parallel lines; most of them are on the order of 75 miles long and a couple of them are 128.”
Brockett has the wheels up by 9 a.m. After the jet clears land, the craft rocks through a quick pitch-and-roll maneuver that calibrates a laser altimeter on board. Everyone wears light green headsets that allow them to talk about changing weather patterns and remaining mission objectives.
Most researchers work on laptops or fine-tune their delicate instruments until Antarctica comes into view and the real work begins.
After 11 parallel passes and numerous wide “teardrop” turns, the DC-8 begins its journey northward. Before returning to the airport, the laser is calibrated again with the stomach-tugging, roller-coaster pitch-and-roll maneuver. Within a half-hour of landing, all hands reassemble for debriefing. Instrument teams report on the day’s work.
KU graduate student Lei Shi speaks for the MCoRDS radar team.
“We gathered data the entire time, about four hours’ worth,” Shi says. “We saw bed reflections coming from the ice shelf when it was thinner so we know that the radar is working, but once we got to some of the thicker areas, our scrolling echogram doesn’t have the processing power to see what’s at the very bed. But I believe that with some more processing, we might be able to pull that out.”
Since the next day looks promising for a flight over sea ice, Brockett announces the morning’s schedule.
“Eight-thirty brief, 10 o’clock take off, close the door at 9:30, pretty standard,” he says.
It’s 9 p.m. before the researchers and flight crew head to their cars. Chileans traditionally eat dinner late, so it’s easy to find an open restaurant. Finding one with the flavors of home, well, that’s a challenge. KU graduate student Ben Panzer voices a craving for a Wendy’s Spicy Chicken Sandwich or Baconator. Three weeks into the mission, he’d settle for just the smell.
Reading the ice
Work continues well into the night.
During one 11-hour, low-altitude flight over the Antarctic Amundsen Sea, the CReSIS team collected more than 330 gigabytes of data from the SNOW radar and 256 gigs from the Ku-band system. It’s equivalent to more than 100 million short plain-text e-mails.
For the students, delivering results translates into several all-nighters of data processing and backup. They survive on power naps.
“The near real-time turnaround of practically science-quality data from our systems is something that we’re pushing,” KU’s Allen says. “We are advancing that capability now through the support of folks from Polar Grid at Indiana University.”
The KU researchers are finding more than just the thickness of the ice and the nature of the bedrock below it. Data images collected over the continent suggest a distinct layer of ice 300 meters from the surface, where it’s likely that sulfur was deposited by a volcanic event millennia ago. The MCoRDS radar also reveals a deep gouge in bedrock that cuts well below sea level. Other early images show ice on the continent as much as 1.8 miles thick.
Wagner stresses it’s not time to rest. ICESat, the aging NASA satellite, indicates change to the ice sheets is here and now.
“ICESat recently showed that some of the ice sheets lose 9 meters of ice per year. That’s ice in elevation. These outlet glaciers are only hundreds of meters thick,” Wagner says. If the current rate of loss had been constant, the ice sheets would have disappeared within 1,000 years. “We know these have been there millions of years, so we know there is change happening today.”
KU researchers are looking at five more years of mowing the lawn. In a jet. Over Antarctica.