Washington, District of Columbia 2021-06-11 14:02:16 –
June 11, 2021
The ice shelves on the Pine Island Glacier in Antarctica lost about one-fifth of their area between 2017 and 2020, most of which were three dramatic breaks. The time-lapse video incorporates satellite images from January 2015 to March 2020. For most of the first two years, the satellite took high-resolution images every 12 days. After that, I captured images of ice shelves every 6 days for more than 3 years. The image is from the Copernicus Sentinel-1 satellite operated by the European Space Agency on behalf of the European Union.
Credits: Joughin et al./Science Advances
For decades, ice shelves that help control one of Antarctica’s fastest-moving glaciers are gradually thinning. Analysis of satellite images has revealed a more dramatic process in recent years. From 2017 to 2020, a large iceberg on the edge of the ice shelf collapsed, accelerating the glacier.
Recent speedups due to edge weakening may shorten the timeline for the Pine Island Glacier to finally collapse into the ocean, as floating ice shelves help reduce the glacier’s larger ground mass. ..The· Research It was published in the open access journal Science Advances on June 11, according to researchers at the University of Washington and the British Antarctic Survey.
“You may not be able to afford the slow changes on Pine Island. In fact, things can go much faster than expected,” said the lead author. Ian Joughin, A glaciologist at the UW Applied Physics Laboratory. “The process we were studying in this area was Irreversible collapse, But at a fairly measured pace. Things can get even worse if you lose the rest of the ice shelf. “
The Pine Island Glacier contains approximately 180 trillion tonnes of ice. This corresponds to 0.5 meters (1.6 feet) of world sea level rise. Much of Antarctica’s contribution to sea level rise is already due, causing about one-sixth millimeter of sea-level rise each year, or about two-thirds of an inch per century, and this rate is expected to increase. I will. If the adjacent Sweat Glacier accelerates and completely flows into the ocean, releasing control over the larger West Antarctic Ice Sheet, the world’s oceans could rise several feet over the next few centuries.
These glaciers have been in the spotlight in recent decades as the ice shelves have become thinner as warmer currents have melted underneath the ice. From the 1990s to 2009, the movement of the Pine Island Glacier into the sea accelerated from 2.5 kilometers per year to 4 kilometers per year (1.5 miles per year to 2.5 miles per year). After that, the glacier velocity stabilized for almost 10 years.
The results show that what happened recently is another process related to glacier internal forces.
From 2017 to 2020, the Pine Island ice shelf is one-fifth of its area with several dramatic breaks captured by the Copernicus Sentinel-1 satellite operated by the European Space Agency on behalf of the European Union. I lost. Researchers analyzed images from January 2015 to March 2020 and found that recent changes in the ice shelf were not caused by processes directly related to ocean melting.
“The ice shelves appear to be torn due to glacier acceleration over the last decade or two,” said Joughin.
Two points on the glacier surface analyzed in the treatise speeded up by 12% between 2017 and 2020. Using an ice flow model developed at UW, the authors confirmed that ice shelf loss caused the observed speedup.
“The recent change in velocity is not due to melting thinning, but instead due to the loss of the outer part of the ice shelf,” says Joughin. “The glacier speedup is not catastrophic at this time, but if the rest of the ice shelf breaks and disappears, the glacier can speed up considerably.”
It is not clear if the shelves will continue to crumble. Other factors, such as the slope of the land below the glacier’s receding edge, will act, Joughin said. However, the results change when the ice shelves on Pineapple disappear and the speed of glacial motion, helping to contribute to sea level rise.
“The loss of ice shelves on Pineapple seems to be likely to occur in the next 10 or 2 years, as opposed to the underground changes caused by melting over 100 years,” the co-authors said. I have. Pierre Dutriu, A physical oceanographer at the British Antarctic Survey. “So it’s potentially a much faster and more abrupt change.”
Pine Island shelves are important because the curved buttresses of Notre Dame cathedral help control this relatively volatile West Antarctica glacier, which is the way the cathedral’s mass is supported. When these buttresses are removed, slow-moving glaciers flow faster toward the ocean, contributing to sea level rise.
“Records of sediments in front of and below the ice shelves on Pine Island show that glacier fronts have been relatively stable for thousands of years,” added Dutrieux. “Regular progress and divisions occurred in about the same place until 2017 and then worsened every year until 2020.”
Other co-authors Daniel Shapero And Ben smith At the University of Washington; Mark Barham of the British Antarctic Survey. This study was funded by the National Science Foundation, NASA, and the British Natural Environment Research Council.
NSF: OPP-1643285, NASA Grant: NNX17AG54G
Edge of Pine Island Glacier’s ice shelf is ripping apart, causing key Antarctic glacier to gain speed Source link Edge of Pine Island Glacier’s ice shelf is ripping apart, causing key Antarctic glacier to gain speed