Norway, U.S. team up for IPY traverse

Posted: October 31, 2007

Courtesy: Antarctic Sun

By Peter Rejcek, Antarctic Sun Editor

Even after 50 years of continuous research across Antarctica by scientists from countries around the world, there are still parts of the icy continent that remain relatively unexplored.

A team of Norwegian and American researchers will take a long trek into one of those unknown areas this austral summer during a 10-week, overland traverse of Dronning Maud Land in East Antarctica. The joint campaign, an International Polar Year (IPY) project, will study how climate variability relates to ice sheet mass and global sea level rise.

The equation is an important one to understand as scientists continue to piece together the jigsaw puzzle of climate change. A warmer climate would naturally cause more melting and calving of icebergs, forcing water levels to rise.

But at the same time, a warmer air mass above the continent would hold more moisture and increase precipitation, possibly offsetting loss in ice sheet mass and perhaps slowing the creep of the ocean to beachfront condos.

There are different hypotheses that say “yea” and “nay” to the idea that precipitation would add significant mass to East Antarctica to counterbalance loss by melting and glaciation, according to Tom Neumann, a polar scientist from the University of Vermont. Neumann will accompany the traverse during its early weeks.

The problem is that both sides of the debate are relying mainly on satellites or models to determine the effect of accumulation rates, explained Mary Albert, principal investigator (PI) and head of the U.S. team. There’s little physical data to corroborate either side —whether the ice sheet is growing or shrinking.

“So we’re going in to find the answer,” said Albert, with Dartmouth College. “We’re going to take the measurements that will show one way or the other.”

Into the unknown
Dronning Maud Land, or Queen Maud Land, is a 2,500,000-square-kilometer wedge that radiates from the South Pole and fans to about 65 degrees of latitude at the coast. The western edge at the widest point abuts the Weddell Sea. The eastern border runs close to 45 degrees East latitude.

The Norwegian-U.S. traverse team will head roughly into the heart of that pie piece, making a roundtrip journey from Troll Station, a Norwegian scientific research base near the coast, to the South Pole over two summer seasons.

The first leg will take the researchers on a southeasterly direction to the Pole of Inaccessibility, the most distant point from the Southern Ocean, before they turn back west to the South Pole. Next year’s journey will pick up at South Pole, following a different and still undetermined route back to Troll Station.

The 4,900-kilometer roundtrip journey will take place in the high elevations of the continent, generally between altitudes of 3,000 and 4,000 meters, Neumann said. Troll Station itself is at about 1,270 meters and the South Pole rises to nearly 3,000 meters.

“From the Pole of Inaccessibility to the South Pole, we’ll be going downhill for the last [900] kilometers,” Neumann noted.

There are some measurements of the area from previous overland traverses, particularly the 1960s and 1970s, he said. But no one has really ventured into the region since then, and certainly not with the modern radars and tools at the team’s disposal.

“It’s about as far as you can get from the coast and air bases, and it’s hard to support logistically,” he said, explaining why the area has been largely terra incognita until now. “The only feasible way of doing it, for now, is through traversing.”

Jan-Gunnar Winther, with the Norwegian Polar Institute and overall PI for the traverse, said the team will cross paths with some past expeditions along certain points of the route.

“We can compare some of the historical data with the modern data that we are collecting,” he said.

“This is in an area that is between the Antarctic Peninsula, where we’ve had radical and rapid disintegration [of ice], and the Ross Ice Shelf side, where we’ve had less change but more precipitation,” Winther added.

Taking measure
The researchers will focus on doing measurements that will allow them to reconstruct the last 1,000 years of climate variability in this part of East Antarctica. They will take several ice cores about 70 meters long as well as shorter cores that will let them examine the last two centuries with more detail.

“By taking a couple of longer cores, we’ll get a nice record of the previous 800 years before the Industrial Revolution, so the changes since then would be much more obvious,” Neumann said.

One of Neumann’s tasks is to conduct stable isotopic measurements of snow and ice samples, a task he will perform once back in the United States and from the samples he and others take in the next few months.

By studying the isotopic ratios of the same element—oxygen 16 and oxygen 18, for instance—researchers can figure out what the climate was doing at a particular time because they can correlate different ratios with different types of climate.

The snow falls with one isotopic ratio. But after it sits around, that number can change because of interaction with the atmosphere.

“Every time water vapor moves around it can change the isotopic ratios,” Neumann said. “We want to study that to be able to better understand this process and account for it when trying to understand past climate.”

Another goal is to look at the surface distribution of stable isotope ratios, which are an important calibration tool for continental circulation models, Neumann said. This will tell researchers “about where certain precipitation is coming from and how much precipitation in different areas get.”

Albert will study the microstructure of snow and how the climate affects the snow’s physical properties. She will look at surface samples and the first 30 meters of ice for her work to understand the physical effects of accumulation rates on the snow.

“Snow as a natural material is always close to its melting point compared to other materials, such as soil,” she said. “Consequently, the microstructure of snow changes a lot in response to local temperature and changes in temperature, and it responds to changes in accumulation.”

Antarctica is a notoriously dry continent, with little precipitation. Most of what does fall occurs at the coast. Albert said the team can expect to see annual snowfall rates of up to 20 centimeters near the coast, tapering off to ice accumulation of less than 2 centimeters at the high, interior areas.

Another important component of Albert’s measurements relate to how snow’s physical properties affect radar signatures. “This will ultimately help us understand what the remote sensing images of Antarctica mean,” she said.

Taking flight
Radar and remote sensors will play a big role in the project, from snooping out crevasses and mapping a route to measure the thickness of the ice sheet and the spatial distribution of snowfall.

One of the more whiz-bang instruments at the team’s disposal is an unmanned aerial vehicle (UAV). The UAV, with a wingspan of nearly four meters, will be launched at each major stop along the traverse route—about nine in total.

“We have an 18-foot-long catapult and use compressed air to launch the plane,” explained Stian Solbø, a research scientist with Norut, a research institution in Norway. Solbø will be on the expedition running the UAV as well as taking GPS and ground-penetrating radar readings.

The UAV carries meteorological instruments, radar and a digital camera. “The radar will be used to measure the thickness of the annual snow layers and the camera images will be used to determine the roughness of the surface, which is important when modeling the redistribution of snow due to winds,” Solbø said via e-mail.

“The flights will be at 600 feet above the surface, which is a compromise between the range of the radar and the area covered with the camera,” he added. The drone will range hundreds of kilometers from each launch site.

“Operating a UAV at the altitude and temperatures of the plateau is very challenging, so this project carries a considerable risk of equipment failure,” Solbø noted. “As anyone living in the Arctic [knows], materials and equipment behave differently at 40 [degrees] below [Celsius] and things break very easily, and all work has to be done with gloves on, so we have attempted to make the system glove proof.”

Getting together
It’s also not easy for people to work at those types of temperatures and altitude.

Each person on the traverse team was chosen for his or her strong polar background, as well as for multiple skill sets, according to Winther. The team is balanced between Norwegian and American scientists.

“It’s a very experienced team that can handle and cope with the challenges that we will meet, like low temperatures and long days and the remoteness,” he said.

For instance, Neumann has worked previously with the International Trans Antarctic Scientific Expedition (ITASE), a similar project that has carried out traverses in other parts of the continent and that will also make a bid for South Pole this season.

This will be Albert’s first traverse, but she has deep-field experience in the Antarctic studying megadunes on the East Antarctic plateau three years ago. “Personally I’ve tried to prepare myself physically, mentally and emotionally. It’s a very long time, and under very severe conditions,” she said.

Though he lives in the Arctic, Solbø said he hasn’t experienced the sort of temperatures the team will encounter on the plateau and will bundle up appropriately. “I have also attended a course on glacier safety given by the Norwegian Polar Institute, where we have trained on rescuing people from crevasses,” he said.

Fifteen people will set out on the expedition from Troll, including three members of the media to document the early weeks of the trip. The journalists and two scientists, along with some cargo, will be airlifted out before the rest of the team continues to the Pole.

“We really operate as a team,” she said. “Everyone knows what’s going on. Everyone has a chance to contribute to the discussions. We all share in the joy of discovery and we all share in the menial tasks that must be done.”

NSF-funded research in this story: Mary Albert, Dartmouth College.

- Antarctic Sun