Scientists at the Jet Propulsion Laboratory of the University of California, Irvine and NASA have for the first time determined how coastal glaciers in the fjords of Greenland are affecting individual glaciers. His work is the subject of a recently published study Science advance.
Working under the auspices of the Ockins Melting Greenland mission for the past five years, researchers used ships and aircraft to survey 226 glaciers in all areas of one of Earth’s largest islands. He found that between 1992 and 2017, about 74 glaciers of Greenland’s total ice loss lie in deep, steep-walled valleys.
Such phased-bound glaciers were discovered to be the most subject to undercutting, a process by which warm, salty water at the bottom of the valley melts ice from below, causing the public to break down more quickly than usual . In contrast, the team found that 51 glaciers deployed in shallow lanes experienced less erosion and contributed about 15 percent of the total snow loss.
Lead author Michael Wood, a post-doctoral researcher at NASA’s Jet Propulsion Laboratory in Southern California, said, “I was surprised how this happened. This largest and deepest glacier is much faster than small glaciers in shallow fjords. Happening.” This research as a doctoral student at UCI. “In other words, the largest glaciers are the most susceptible to hot water and they are actually driving the loss of Greenland’s ice.”
The study also highlighted the dynamic allowing the intrusion of warmer ocean waters into deeper plains than shallow ones, accelerating the process of undercutting along Greenland’s largest glaciers.
Greenland is one of only two ice sheets on Earth, the largest being Antarctica. The snow in Greenland is more than two miles (three kilometers) thick. At the edges of the land mass, huge glaciers spread by a sheet of ice travel slowly up the valleys, like the icy conveyor belt, which penetrates in inches and then melts or breaks as an iceberg. The ice is periodically compacted by ice packs.
If the ice sheet was in equilibrium, the amount of ice accumulating at the top would be roughly equal to the ice lost from melt, evaporation, and calving, which floated in the ocean, free from anchored masses.
But the ice sheet has been out of balance since the 1990s. The melting has intensified and calving has increased, causing the glaciers to move back into the sea towards land. Together, these result in ice sheet shrinkage.
According to the research team, the rise in temperature in the summer months has accelerated the formation of warm salty water at the bottom of the phasers, which heats the surfaces of the glaciers, causing melting. This liquid leaks through cracks in the ice to form subsurface freshwater rivers that flow into the ocean where it interacts with saltwater beneath the fjords.
The glacier molten water is free of salt, so it is lighter than seawater and rises to the surface and draws hot water in the form of a plume and keeps it in contact with the glacier bottles. Fjord depth is a fairly irreversible factor, but other factors such as the temperature of seawater and the amount of water melted from the surface of glaciers are greatly influenced by climate warming. All three factors cause a rapid deterioration of Greenland’s ice sheet, the researchers said.
As water temperatures around the coast of Greenland are projected to continue to rise in the future, these findings suggest that some climate models may damage at least two of the glaciers if they are undercutting by a warm ocean. Are not responsible for
The study also explains why many of Greenland’s glaciers never recovered after a sudden ocean warm-up between 1998 and 2007, raising sea temperatures by about 2 degrees Celsius. Although the ocean’s warming had stopped between 2008 and 2017, glaciers had already experienced extremes in the last decade that they continued to retreat at an accelerated pace.
According to OMG Deputy Principal Investigator Eric Rignot, JPL and UCI, “We have known for over a decade that the Warmer Ocean plays a major role in the development of Greenland glaciers.” “But for the first time, we have been able to reduce the impact of the retreat of the glacier over the last 20 years and demonstrate its major impact.”
Warming Greenland’s ice sheet is the point of no return
Michael Wood et al, Forced ocean forcing glacier retreat in Greenland, Science advance (2021). DOI: 10.1126 / Sciadv.aba7282
University of California, Irvine
Quotes: Rising sea temperature recovers Greenland’s ice sheet (2021, 25 January) on 26 January 2021 from https://phys.org/news/2021-01-ocean-temper-threatens-greenland-ice.html is.
This document is subject to copyright. No part may be reproduced without written permission, except for any fair that serves for the purpose of personal study or research. The content is provided for information purposes only.