Scientists expected a delivery event when a block of ice about the size of Houston, Texas separated from the Amery Ice Shelf in East Antarctica in 2019, but did not know exactly where it would occur. did. According to researchers, satellite data now helps scientists measure the depth and shape of ice shelf crevices to more accurately predict when and where labor events will occur.
Shujie Wang, an assistant professor of geography at Penn State University, says ice shelves occupy nearly 75% of Antarctica’s coastline and buttresses, controlling larger glaciers on land. If ice shelves collapse and Antarctic glaciers fall or melt into the ocean, sea level can rise up to 200 feet.
“When trying to predict the future contribution of Antarctica to sea level rise, the greatest uncertainty is ice shelf stability,” said Wang, who has also been appointed to the Institute for Global Environmental Systems. “There is no easy way to map the depth of fractures in the field on a regional scale. Satellite data can capture the depth and surface morphology of ice shelf crevices, thereby providing extensive and consistent monitoring of this information. I understand. “
Wang and her colleagues were collected by ice, cloud, and land elevation satellites (ICESat-2) between October 2018 and November 2019 on the Amery shelf ice, which is about the size of West Virginia. I examined high resolution data. The laser sends a pulse to the land surface and uses reflected photons to determine the height of the surface. While other satellites have resolutions of thousands of feet, ICESat-2 has a resolution of about 56 feet, so you can see small crevices and morphology of crevices.
Researchers then ran ICESat-2 data via an algorithm that characterizes surface depressions to find and characterize ice crevices.They reported their results in the journal Remote sensing of the environment..
Researchers have identified three types of ice shelf crevices (U-shaped, parabolic, and V-shaped) up to a depth of 164 feet. They also found that this surface information provided insight into what was happening hundreds of feet below the surface of the ice.
According to the king, the morphology of skull base fractures (the shape and size of fractures at the bottom of the ice shelf) is proportional to the surface depression. As the glaciers supported by the ice sheet accumulate more snow and ice, parabolic crevices flow toward the edges of the ice shelves. As they cross certain boundaries, their surface fractures are more likely to penetrate deeper into the ice as the skull base fractures grow upwards. These crevices will be V-shaped, which may indicate the formation of a lift (a crevice that penetrates the entire thickness of the ice sheet). These crevices are more likely to cause labor events.
“Incorporating satellite-based vertical information can improve future ice shelf models,” Wang said. “This helps us to actually predict where delivery fronts and ice shelves are vulnerable to these events.”
Other contributors to this study included Patrick Alexander and Marco Tedesco, Columbia University’s Lamont-Doherty Earth Observatory, and NASA Goddard Institute for Space Science. University of Tennessee Qiusheng Wu; Song Shu of Appalachian State University.
The National Science Foundation and NASA supported this research.
NASA’s ICESat-2 satellite reveals the shape and depth of Antarctic ice shelf crevices – so watt-up?
https://wattsupwiththat.com/2021/03/05/nasas-icesat-2-satellite-reveals-shape-depth-of-antarctic-ice-shelf-fractures/ NASA’s ICESat-2 satellite reveals the shape and depth of Antarctic ice shelf crevices – so watt-up?