A Twin Otter aircraft carrying a gravimeter developed in Ottawa prepares to land after testing the device at the North Pole. ((Stefan Elieff/Sander Geophysics))

An Ottawa technology company is drawing on gravity to pull out the secrets of a massive hidden mountain range from underneath a sheet of Antarctic ice four kilometres thick.

Scientists from Sander Geophysics Limited are leaving next week as part of the Gamburtsev Province Project, an international Antarctic expedition related to the International Polar Year.

The project will map the mysterious Gamburstev mountain range and its lakes, which are buried under glacial ice that is more than a million years old. That ice, and the gases and particles that have been trapped in it over the eons, is expected to provide information about climate change in the past in order to understand change going on now.

Luke Copland, a geography professor at the University of Ottawa who studies the glaciers of Antarctica, said that eastern part of the continent is poorly understood.

"We don't really know what's beneath the ice sheet," he said.


Staff pack up the Airgrav device at the company's Ottawa headquarters. ((CBC))

The Ottawa team will be joining groups from the United States National Science Foundation, the British Antarctic Survey, the German Federal Institute for Geosciences and Natural Resources (BGR), Australian Antarctic Division, Chinese Arctic and Antarctic Administration and the Japanese National Institute of Polar Research that will conduct a series of air surveys as well as surveys on the ground using seismometers, which measure motions within the ground.

Luise Sander, co-president of Sander Geophysics with her brother Stephan, said her father George was very proud of the Airgrav, the made-in-Canada instrument that will be used in the air surveys that will be part of the upcoming project. George Sander founded the company 50 years ago as a one-man operation that went on to fund the research and development of the device, which was originally designed to look for oil.

"It was developed in-house by our own people," said Martin Bates, who helps process the data collected by the instrument. "It is the best instrument of its kind that's operating at this time and I'm pretty proud to be part of that."

Anything with mass has a gravitational field that attracts other objects with mass, and the more massive it is, the stronger its gravitational field. The Airgrav is a device called a gravimeter that measures small changes in the local gravitational field based on the acceleration caused by gravity.

One millionth of normal gravitational field

"We're trying to measure about one one-millionth of the normal gravity field that you feel," said Stefan Elieff, who has been a geophysicist with Sander for 10 years.

The measurements provide information about the distribution of materials with different masses or densities, such as ice, rock, or oil.

Airgrav is specially designed to take measurements from a plane as it flies in a grid pattern over the course of a month. Careful data processing is then done to remove the acceleration caused by the movement of the plane, leaving behind the changes in acceleration caused by changes in the gravitational field.

The measurements are then assembled into a map, Elieff said.

The instrument has already been installed in a Twin Otter aircraft and has performed well in tests in the Arctic, the company said.