The largest Antarctic traverse since the 1950s took years to plan logistically and its success was largely due to information provided by satellites. Photo / Neil Silverwood
The largest Antarctic traverse since the 1950s took years to plan logistically and its success was largely due to information provided by satellites. Photo / Neil Silverwood
A University of Canterbury glaciologist has navigated a second expedition across the world's largest ice shelf, to enable vital insights into Antarctica's vulnerability to climate change.
Dr Dan Price recently returned to Scott Base after making a six-week 1100km traverse of the enormous Ross Ice Shelf, to reach a remote and wild area called the Siple Coast.
Here, where the West Antarctic Ice Sheet lifts off the seabed and starts to float, scientists could find tell-tale signals of conditions that led to the retreat of glaciers and sea level rise.
A research team led by renowned Antarctic scientist Professor Gary Wilson of Otago University surveyed the area using a gravity meter and explosives to trigger seismic waves.
But reaching this important spot had been fraught with difficulty – and attempts to get there by aircraft had failed.
That left Price and a small team to try forging a path across some of the most perilous terrain on the continent, in what proved the largest Antarctic traverse since the Commonwealth Trans-Antarctic expedition in the 1950s.
While he'd spent several seasons on the ice as a research scientist, last summer was his first stint in an operations effort for Antarctica New Zealand.
"I got approached to plan a route across to the Siple Coast because no one has ever driven to it," he said.
"There are sections that are heavily crevassed, but the surface of the ice shelf is flat and white, these crevasses are completely hidden from the naked eye."
Back in Sir Edmund Hillary's famed time in Antarctica, making such a journey would have involved peril at every turn.
Each year, the France-sized ice shelf stretched by about 400m, carving past the McMurdo Ice Shelf, which was moving an annual 50m.
This created what's called a shear zone where the ice shredded and left deep crevasses later concealed by snow.
"Without technology to help you, trying to find a path over this kind of landscape would just be about luck – you might try to read the terrain, but in certain areas that doesn't tell you anything at all."
Fortunately, the team was able to plot their route with TerraSAR-X – a satellite mission operated by the German Aerospace Centre (DLR).
Microwave energy sent out by the satellite interacted with the surface of the ice and bounced back to space, allowing scientists to effectively take an X-ray of the shelf and its hidden traps.
"We can use this data to weave in and out of the hazards – without it we'd be navigating a minefield blindfolded."
The team nonetheless had to take their own precautions.
The main safety concern getting across the ice shelf was crevassing. Photo / Neil Silverwood
One of their three PistenBully vehicles, often used as snow groomers on Kiwi skifields, was fitted with an eight-metre boom with radar technology that constantly scanned the ground ahead of them.
"You could monitor it on a screen in the vehicle in real-time – and if a crevasse was coming up, you had a five-second window to stop."
The pre-plotted path proved reliable enough that this didn't happen.
This season, Price and colleagues repeated the trip - this time to carry out gear for Wilson's team – before carrying on another 150km to a US station at Siple Dome.
The trips could be exhausting, and not just because much of them were spent constantly focused on a screen.
"You drive for 10 to 12 hours a day, and then you sleep in the back of our vehicles, and you kind of get fatigued mentally."
The weather was generally settled on the second expedition and temperatures reached as low as -19C.
"When we left base on the first traverse it was -40; in those conditions the vehicles don't work properly and everything becomes more difficult," he said.
"On the way back, the worst conditions were when it was basically white-out, because you've got zero ground-definition you just feel like you're floating.
"The horizon blends into the ground, you can't see anything, and you're navigating by GPS, which gets really tiring."
But Price – a scientist passionate about climate action, and who made an awareness-raising odyssey from Antarctica to France in the months ahead of the landmark 2015 UN summit in Paris – felt satisfied to be aiding vital research.
"Attempting to understand how the Ross Ice Shelf is going to respond to warming is a massive question, because it's buttressing the incredibly vulnerable West Antarctic Ice Sheet and a huge chunk of the East Antarctic Ice Sheet," he said.
"You're talking about several metres of potential sea level rise that is being held in place, and the data that will come back from the Siple Coast will be extremely valuable.
"Yet, in the end, it all comes back to climate action. We can do the science and then say the sea level is going to rise by a specific amount, but if no one actually does anything about it, we're still in the same position.
"So I think it's all about ensuring that the urgency surrounding this science is effectively communicated to the right people and that we ultimately do the right thing – that's to decarbonise as quickly as we can."
• Jamie Morton is hosted at Scott Base by Antarctica New Zealand.
