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23 August 2016

New Mapping Process Reveals Ice-Free Regions of Antarctica

Antarctica, a vastly unexplored continent hovering on the edge of our collective consciousness, far removed to the point of dismissal without much thought; after all, visiting this uninhabited ice block is a feat for only the most weather-beaten individuals. That’s how I assume us normals feel, but look at this terrain of snow and ice with a science-minded approach.

It’s a veritable desert, the coldest, windiest, driest continent on Earth, and it’s absolutely covered in ice. Until recently, scientists have only been able to estimate the percentage of land not dominated by frozen substances at less than 1%. Thanks to new mapping technologies, it has been proven that a mere 0.18% of Antarctica is ice and snow free, half the amount estimated. This discovery has set a baseline against which to measure the rate of global warming.

Why is this important?

Historically, maps of Antarctica have been inaccurate because of the way that mapping was done. Thanks to the inhospitable land and unyielding ice, scientists had to resort to low latitude satellite images to map out the lay of the land. These images were often made unclear or distorted by shade and cloud cover, meaning that rocky outcrops had shaky borders, and trying to discern what was snow-covered versus snow-free was no easy feat.

3,150 individual satellite images fused to create this map - Img source:
Utilising NASA and US Geological Survey satellite data to compile a map of all rock outcrops on the continent, lead author Alex Burton-Johnson was finally able to create a much-needed definitive map of Antarctica. With the help of his colleagues, Burton-Johnson developed a system capable of differentiating between snow and rock. It can detect sunlit and shaded rock as positively as it does snow, clouds, and liquid water. Suffice it to say, this is a highly accurate method of mapping. This effectively trumps the previous method of satellite imagery analysis.

This monumental improvement has an accompanying article published in Cryosphere. Before this, when low latitude satellite images were interpreted, scientists drew rock outcrops by hand. Burton-Johnson and company were able to automate the process, minimizing any potential inaccuracies. An automaton has been installed and is ready to receive new satellite images, meticulously tracking any changes to the South Pole.

The findings of this new mapping system are slightly encouraging, as they undercut scientists’ previous estimation by a fair amount. In simple terms, 0.18% translates to 8,396 square miles or 21,745 square kilometres. To put that in perspective, the total surface area of Antarctica is 5.4 million square miles or 14 million square kilometres. With accurate maps documenting ice-free rock, scientists studying glaciology, geology and mapping will have a better grasp on any developments in climate change. 

Jacqui Litvan

Jacqui Litvan, wielding a bachelor's degree in English, strives to create a world of fantasy amidst the ever-changing landscape of military life. Attempting to become a writer, she fuels herself with coffee (working as a barista) and music (spending free time as a raver).