Sea ice in the Antarctic may be thicker than previously thought.
Although the extent of Antarctic sea ice is easily tracked by satellites, estimating the thickness of the ice has proven challenging.
Guy Williams of the University of Tasmania, Ted Maksym from Woods Hole Oceanographic Institution, Jeremy Wilkinson of the British Antarctic Survey and colleagues used an autonomous underwater vehicle in 2010 and 2012 to map the thickness of sea ice across several coastal regions of Antarctica.
The researchers found that the thickness of the ice beneath sea level was 1.4 to 5.5 metres on average.
The thickest sea ice was 16 metres.
Although submarines have been used to document Arctic sea-ice thickness 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.
The extensive observations by the underwater vehicles in this study reveal a greater thickness of Antarctic sea ice, and will also aid projections of the response of sea ice to climate change.
A yellow SeaBED robot, which is two meters long and weighs nearly 200 kilograms, with a twin-hull design was used for the survey.
The next steps are for large-scale surveys which can be compared to observations from aircraft and satellites.
The sea ice study is reported in the journal Nature Geoscience.
Here’s the survey in action:
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