An underwater robot has helped scientists from the USA, UK and Australia accurately measure the thickness of Antarctic sea ice, even from the areas that were previously considered too difficult to access. The underwater revealed that the Antarctic ice is much thicker than previously feared. It is a major step forward in the ongoing mystery of the expansion in Antarctic sea ice.
Underwater robot provides a nice solution
Climate models suggest that the region’s sea ice should be melting every year due to global warming. However, satellite observations indicate that the ice is expanding. Measuring the thickness of sea ice will help scientists understand what is driving the growth in sea ice. However, measuring the sea ice thickness had long been a tricky task.
Surface snow leads to error in satellite measurements. And it’s quite difficult to take direct measurements from ship or drilling. But an underwater robot provided a nice solution. The Autonomous Underwater Vehicles (AUV) called SeaBED were launched off an Australian and a British ship at three sites in the Antarctic Peninsula. The remote-controlled underwater robots were fitted with upward-looking sonar to map and measure the underside of sea ice floes.
Sea ice was as thick as 55 feet
The AUVs operated at a depth of 65 to 100 feet (20-30 meters), and were driven in a lawnmower pattern. Scientists were able to capture detailed, high-resolution 3D maps of the Antarctic sea ice. The underwater robots covered an area of 500,000 square miles. Ted Maksym, lead author of the study, said that the ice in some places as thick as 55 feet.
However, the average thickness was much less. On average, the Antarctic sea ice was 4.6 to 18 feet thick. In the three regions studied, the underwater robots found that thickened, deformed ice accounted for 50% to 76% of the total ice volume. Maksym said that though his team didn’t measure all Antarctic sea ice, this study was a “huge step” towards more routine studies needed to answer whether the Antarctic sea ice is getting thicker.
Findings of the study were published in the journal Nature Geoscience.