Underwater vehicle to measure Antarctic Sea ice

In a bid to get a better understanding of the effects of global climate change, New Zealand scientists will begin a project to measure Antarctic sea ice from below this coming southern summer.

Using a remote underwater vehicle, University of Canterbury professor Ian Hawes will measure the thickness and biological productivity of Antarctic Sea ice to understand its role in ocean circulation and the functioning of polar ecosystems, Xinhua reported.

Other than spot drilling, measuring sea ice is extremely difficult because of its inaccessibility, Hawes said in a statement Wednesday.

"At the same time, we know that sea ice properties are variable over distances of a few metres. Information from satellites is very limited too as they can only tell us the elevation of the ice surface," he said.

The underwater vehicle will take measurements with finer resolution over greater distances to help measure ice properties in a much more robust way.

Sea ice comes in two types - pack ice and fast ice. Fast ice is attached to land and is safe to access and drill holes for only part of the year. Pack ice is not attached to land, but occurs as broken up floes that can only be accessed by some ships.

"This has put major limitations on where we can sample and how many samples can be obtained," Hawes said.

"Our cutting-edge project will produce accurate information on sea ice thickness and the biomass of algae growing in the ice, information which is of global significance for better understanding linkages between ice dynamics, ecosystems and climate change," he noted.

Sea ice varies depending on its age, but scientists are expecting it to be two to three metres thick.