A war-era DC-3 aircraft is playing an unlikely role in a state-of-the-art scientific survey of Antarctica's intriguing sea ice.

University of Canterbury glaciologist Dr Wolfgang Rack is leading the world's first "EM-bird" measurement of sea ice thickness using a 1942-built, fixed-wing plane.

The survey, based in McMurdo Sound, aimed to explore how much sea water was freezing in the Southern Ocean every year and how important that was to the planet's climate.

Scientists know the sea ice plays a crucial, yet poorly understood, role in the climate system, helping maintain the cold conditions that ultimately sustain the continent, while also influencing storms across the Southern Hemisphere and affecting the amount of heat the Southern Ocean can absorb as the Earth warms.


But some of the sea ice's most intriguing behaviour isn't captured by the giant Earth System Model (ESM) used to predict our planet's future climate.

EM-bird observations collected by New Zealanders are contributing to an improved ESM able to create region-specific forecasts of future climate for New Zealand and its nearest neighbours.

"Sea-ice thickness is the biggest unknown in cryosphere research, because it is so hard to measure," Rack said.

"It amazes me how little we know about it, despite its significance for global climate."

The EM-bird ("EM" refers to electro-magnetic induction) is the only instrument which can measure the thickness of sea ice remotely, working in a similar way to induction cook-tops, Rack said.

"Because sea ice is salty, conventional radar cannot measure thickness, but the EM instrument can, although it needs to be operated close to the surface."

For the measurements, the research team, dubbed "The Icetronauts", used the converted DC-3 aeroplane to tow the EM-bird at a height of 15 metres above the Antarctic sea ice.

"We are happy to be the first researchers who have shown that the EM-bird can be operated in Antarctica safely from an aeroplane."

Field measurements of sea ice thickness and ocean properties were also made.

Specifically, the data was being used to verify aircraft and satellite measurements to derive ice thickness maps in the Southern Ocean, as part of a PhD study at Gateway Antarctica by Canterbury University student Gemma Brett.

University of Canterbury doctoral student Gemma Brett in Antarctica. Photo / University of Canterbury
University of Canterbury doctoral student Gemma Brett in Antarctica. Photo / University of Canterbury

Her own field work on the ice involved a similar survey but using a much older vehicle.

"For my PhD, I am using an instrument which is very similar to the EM-bird except it is ground-based. It is sled-mounted and I towed it behind a Ski-Doo across the sea ice," Brett said.

Renowned US glaciologist to speak in Wellington

Meanwhile, the world's most prominent glaciologists are to converge on New Zealand for a high-level symposium, one of them the US expert behind a landmark report revealing the unstoppable collapse of a large part of Antarctica.

The group of top international scholars will gather at Victoria University next week to discuss the connections between Earth's frozen waters and the global climate system.

The International Symposium on The Cryosphere in a Changing Climate is the first gathering of its kind to bring together three leading organisations in the field of cryospheric research: the International Glaciological Society, the International Association of Cryospheric Sciences/International Union of Geodesy and Geophysics and the World Climate Research Programme Climate and Cryosphere Project.

The five-day symposium will look at various aspects of the cryosphere, the frozen parts of the Earth, including glaciers and ice sheets, ice cores, sea ice, snow and sea-level change.

Read more: Antarctica: Science at the end of the Earth

One of the visiting scientists, world-renowned glaciologist Professor Eric Rignot, will also be giving a free public lecture at Victoria University on Tuesday evening.

Rignot, who is based at the University of California, Irvine, and NASA's Jet Propulsion Laboratory, has studied the world's largest glaciers in Greenland and Antarctica since the early 1990s, when NASA and other international space agencies first started collecting satellite data on them.

The remnants of the Larsen B Ice Shelf in the Weddell Sea, Antarctica, in 2015. Photo / Ted Scambos, NSIDC
The remnants of the Larsen B Ice Shelf in the Weddell Sea, Antarctica, in 2015. Photo / Ted Scambos, NSIDC

He is best known for ground-breaking research in 2014 which revealed the rapidly melting section of the West Antarctic Ice Sheet appeared to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea.

"We are running out of time to combat climate change," he said.

"Every year that passes by that we aren't doing anything about it just adds up to the problem."

In his lecture, held from 5.30pm in Lecture Theatre 1 in Rutherford House, at the university's Pipitea Campus, Rignot will discuss the current knowledge of ice sheet mass balance and its potential to raise global sea-level by many metres.

"The ice sheets in Greenland and Antarctica are contributing faster, sooner and more significantly than expected to global sea level rise.

"Observations and physics principles suggest sea level rise of more than one metre by 2100, and geological information from 125,000 years and computer models ago suggests a potential for multi metre sea-level rise in the centuries to come."

He will also explore emission mitigation options that could limit the amount of sea level rise.

Other leading scientists travelling to Wellington include Professor Dorthe Dahl Jensen from the University of Copenhagen, Professor Ben Marzeion from the University of Bremen, Professor Rob DeConto from University of Massachusetts and Michael White, senior editor at international journal Nature.