Visiting Antarctica is a bucket-list item for many people – something they hope they can do once in their lives.
Lincoln Agritech research scientist Adrian Tan has gone one better – he’s just returned from his second two-week stay on the frozen continent. Both times, he’s been part of a project researching and testing methods of measuring the thickness of sea ice below the snow pack.
Sea ice drives the world’s weather by influencing the major ocean currents as it forms and melts. It also reflects solar heat back into space. Less sea ice means disrupted currents, disrupted weather, and a warmer world.
Measuring the amount of sea ice is important for forecasting climate and weather. But our present measuring tools aren’t accurate enough.
“It’s easy to measure the extent of sea ice by using satellites, but they are not very accurate at measuring thickness,” says Adrian. “The thickness and the extent will tell us the volume.”
To accurately measure thickness, scientists have been limited to taking manual measurements from one place at a time.
This research team, led by Assoc Prof Wolfgang Rack of the University of Canterbury, is testing a three-part measurement device, suspended under a helicopter, 15m above the snow pack. As it flies over, one instrument measures the distance to the top of the snow, a second measures the distance to the top of the sea water, and the final radar instrument measures snow depth. From that, laboratory tests had shown all instruments together could accurately calculate the thickness of the sea ice.
So, did it work? “It was successful, I’m glad to say,” says Adrian.
However, there are some issues. The combination device gives several sets of data from which the sea ice has to be calculated manually – the aim is to get the final measurement automatically.
Also, to measure large areas, the measuring device would be better suspended from a fixed-wing plane with a larger range than the helicopter.
Adrian says further work – which will require extra funding – will investigate automatically combining the measurements to get one final set of data. The next step will then be to measure the ice at the same time as a satellite is also taking measurements. The comparison will provide a formula for correcting satellite measurements, so sea ice can be measured wherever it occurs, not just on the Ross Sea, where this work took place.
The research team owes a lot of thanks to the Antarctica New Zealand team who hosted them for their two-week stay, says Adrian. “Because we were there for a short period of time, we really needed to concentrate on the science.”
With long sunlight hours, they were able to work from 8am to 10pm most days, with the crew at Scott Base taking care of their every need. “We were basically pampered.”Main image: The measurement device is lifted up by the helicopter.