The gigantic cavity, 40 kilometers square and 300 meters high, grows at the bottom of the Thwaites glacier in western Antarctica, and confirms that this ice mass disintegrates.
It also highlights the need for detailed observations on the lower part of the Antarctic glaciers to calculate the speed with which sea levels will increase in response to climate change.
The researchers hoped to find some gaps between ice and rock at the base of Thwaites, where sea water can flow and melt the glacier from below.
The size and the explosive growth rate of the new hole surprised. It is big enough to keep 14 billion tons of ice, and most of that ice has melted in the last three years.
"We suspected years ago that Thwaites was not well linked to the underlying rock," said Eric Rignot, from the University of California, Irvine, and the Jet Propulsion Laboratory (JPL) of NASA. Rignot is co-author of the new study, which
is published in Science Advancements. "Thanks to a new generation of satellites, we can finally see the details," he said.
The cavity was revealed by an ice penetration radar at NASA's IceBridge Operation, an air campaign that began in 2010 and studies connections between polar regions and the global climate.
The researchers also used data from a constellation of synthetic opening radars of the Italian and German spacecraft. This high resolution information can be processed by a technique called radar interferometry to reveal how the surface of the ground then moved between the images.
"[El tamaño de] The cavity under a glacier plays an important role in the merger, "said the principal author of the study, Pietro Milillo, of JPL." As more heat and water penetrate the glacier, it has melted faster, "he said.
Numerical ice cream models use a fixed shape to represent a cavity under ice, instead of allowing the cavity to change and grow. The new discovery implies that this limitation probably makes these models underestimate the speed with which Thwaites is losing ice.
The Thwaites Glacier, the size of the state of Florida, EE. It is currently responsible for approximately 4% of the level of sea level worldwide. It has enough ice to raise the world ocean a little more than 2 centimeters and house neighboring glaciers, which would raise sea level by 2.4 inches if all the ice was lost.
Thwaites is one of the most difficult places to reach on Earth, but is about to be better known than ever. The National Science Foundation of the United States and the National Council of Environmental Research of the United Kingdom are creating a five-year field project to answer the most important questions about its processes and characteristics. The International Thwaites Glacier Collaboration will begin its field experiments in the summer of the southern hemisphere of 2019-20.
The huge cavern is under the main trunk of the glacier on its western side, the farthest side of the Western Antarctic Peninsula. In this region, as the tide rises and falls, the earth connection line retreats and advances through an area of approximately 3 to 5 kilometers.
The glacier has been separated from a rocky crest at a constant rate of approximately 0.6 to 0.8 kilometers per year since 1992. Despite this stable rate of withdrawal on the land line, the fusion rate On this side of the glacier is extremely high.