27 Feb. () –
Glaciers on the Antarctic coast flow faster in summer due to melting ice and warming ocean waters, researchers report in the journal ‘Nature Geoscience’.
On average, glaciers move about a kilometer a year, but the new study has found a seasonal variation in the speed of ice flow, which accelerates up to 22% in summer, when temperatures are warmer. This gives an idea of how climate change could affect the behavior of glaciers and the role they could play in rising sea levels.
Until now, study of the rugged Antarctic Peninsula has been limited due to the difficulties scientists encounter in accessing the glaciers and conducting field work, but from space, advances in satellite technology are revealing new data on the speed at which glaciers they move and drain water into the surrounding ocean.
The Antarctic Peninsula is the largest reservoir of frozen water on Earth. It is estimated that between 1992 and 2017, meltwater from glaciers raised global sea level by about 7.6 mm. How can this change in the future? one of the great uncertainties in the modeling of climate change.
A team of researchers, led by scientists from the University of Leeds (UK), has used more than 10,000 satellite images, taken over the Antarctic Peninsula between 2014 and 2021to understand how the flow of glaciers into the waters surrounding Antarctica is altered during the coldest and warmest periods.
Ben Wallis, PhD researcher and first author of the study, notes, “One of the important takeaways from this study is that it reveals just how sensitive Antarctic glaciers are to the environment. We have known for some time that Greenland’s glaciers behave seasonal, but it is now when the data obtained by satellite have shown a similar behavior in Antarctica”, he adds.
The Antarctic Peninsula is the northernmost and warmest region of Antarctica. It has 1,000km of mountainous backbone, similar to the length of Britain’s east coast, and is home to a rich marine ecosystem of seals, penguins and whales. Along the west coast of the peninsula, glaciers drain ice from the ice sheet directly into the Southern Ocean.
The analysis of the data obtained by satellite showed that the acceleration of the glaciers occurs in summer, when the snow melts and the temperature of the waters of the Southern Ocean increases. The water from the melted snow is believed to act as a lubricant between the ice sheet and the underlying rock. As a result, friction is reduced and the speed at which glaciers slide increases.
In addition, the warmer waters of the Southern Ocean erode the front of the moving ice, which reduces the reinforcing forces it exerts to resist ice flow.
Dr Anna Hogg, Associate Professor at the Institute of Climate and Atmospheric Sciences in Leeds and author of the paper, notes that “the Antarctic Peninsula has experienced some of the fastest warming of any region on Earth. Continued work like this will help glaciologists to control the speed with which changes occur, This will allow us to accurately assess how Earth’s ice will respond to climate change.”
The European Space Agency/European Commission Copernicus Sentinel-1 satellite, whose data was used in this study, tracks the entire Antarctic coastline on a weekly basis.
The satellite is equipped with synthetic aperture radar that can “see” through clouds, which allows to make measurements of the glaciers both during the day and at night.
In the words of Craig Donlon of the European Space Agency, “This study highlights how high-resolution satellite imagery can help us track the changing environment in remote regions. Future satellites, such as the family of expansion Copernicus Sentinel –continues–, promise to provide continuity and improved capabilities that will allow a deeper understanding of the characteristics and the processes that govern the balance of ice masses and the rise of the sea level”.