Sea ice in the Antarctic may be thicker than previously thought, according to a study published in the Nature Geoscience journal.
The first detailed 3D imagery of Antarctic ice has been released, mapped out by underwater robots capable of reaching areas that were previously too difficult to reach.
"We can now measure ice in far greater detail and were excited to measure ice up to 17 metres thick," says the study's co-author Dr Jeremy Wilkinson from British Antarctic Survey.
Scientists from the United Kingdom, USA and Australia used unmanned underwater vehicles in 2010 and 2012 to map the thickness of sea ice across several coastal regions of Antarctica.
The researchers found that, on average, the thickness of the ice beneath sea level was 1.4 to 5.5 metres, with the thickest sea ice measured at 17 metres.
"What this effort does is show that observations from AUVs (autonomous underwater vehicle) under the ice are possible and there is a very rich data set that you can get from them," says Ted Maksym, a WHOI scientist and co-author of the paper.
"This work is an important step toward making the kinds of routine measurements we need in order to really monitor and understand what's happening with the ice and the large scale changes that are occurring."
The study's authors say although submarines have been used to document Arctic sea-ice thicknesses in previous studies, Antarctic measurements have been limited to shipboard observations and drill holes.
Those limited studies had suggested that most sea ice is thinner than a metre.