Warm ocean water seeping under some glaciers could eventually lead to sea level rise twice as high as currently estimated.
GEORGIA TECHNOLOGY INSTITUTE
The melting of ice sheets at the points where they float on and along the world’s oceans is a major climate culprit when it comes to sea level rise. But the extent to which warm, salty sea water seeps below the “underground” parts of the ice sheets along land is not fully understood, nor what happens when that mix penetrates deep. into the glacier interior.
ONE new research published year Cryosphere do Alexander Robelan assistant professor in School of Earth and Atmospheric Sciences, can provide some clarity. Robel, the leader Ice & Climate Group in Georgia Techand his team of researchers have developed a theory that ice melt may occur out of sight faster than previously estimated.
“The paper shows that warm ocean water can penetrate beneath glaciers, and if it causes melting at the bottom of the glaciers, could double predictions of future sea-level rise,” said Robel. times the current estimate. “In other words, our study has shown that the landfall (where glaciers meet water) is not the kind of impenetrable barrier between glaciers and oceans that was previously assumed.”
Using predictions based on mathematical and computational models, the study shows that seawater intrusion on flat or sloping impervious subsoils can occur up to tens of kilometers upstream. flow of a glacier terminal or ground line.
Freshwater melts at roughly the temperature of the ice it produces, but salty seawater entering glaciers can also carry heat from the ocean, which the researchers say is likely to cause a rapid rate of melting. flows at the bottom of the glacier much higher.
Robel’s co-authors for the study are Earle Wilsona postdoctoral scholar at California Institute of Technologyand Helene Seroussian associate professor at Dartmouth College.
New research uses basic mathematical theory of fluid flow and mainframe models running on Collaboration for a high-performance computing cluster in the Advanced Computing Environment (PACE) at Georgia Tech to make your predictions and build on a 2020 research led by Wilson showed how such intrusions could happen through laboratory experiments.
“Past measurements from field expeditions and satellites have suggested that seawater can enter meltwater channels under ice,” notes Wilson, in the same way that oceans can flow upstream. and mixed with river water in a typical estuary. Our study shows that subglacial estuaries are not only viable but also likely to occur under a wide range of realistic scenarios, and their existence has profound implications for sea level rise. Future. “
“Simulations show that even just a few hundred meters of fundamental sea-based melting upstream of sea-iceberg groundings can lead to higher forecasts of sea ice loss,” explains Robel. 10-50%”. “Kings of fundamental melting due to intrusion could cause the loss of ice mass projected to more than double over the next century.”
Robel adds that these results suggest that further observational, experimental and numerical investigations are needed to determine the conditions under which seawater infiltration occurs – and whether it actually promotes rapid retreat of sea ice and future sea level rise. The team will begin looking at measurements from previous field expeditions to confirm if their theory is correct and are working to secure funding next year to go to Antarctica and search such infiltration during a targeted expedition.
“Overall, this contributes to an important group of work now that is trying to estimate how quickly ice sheets melt under changing climates,” adds Robel, “ and what physical processes are involved in driving these rapid changes”.
DOI: https://doi.org/10.5194/tc-16-451-2022
The Georgia Institute of Technology, or Georgia Tech, is one of the top 10 public research universities that is developing leaders who advance technology and improve the human condition. The institute offers degrees in business, computing, design, engineering, liberal arts and sciences. The university’s nearly 44,000 students, representing 50 states and 149 countries, study at its main campus in Atlanta, at campuses in France and China, through distance learning and online. As a leading technology university, Georgia Tech is an engine of economic growth for Georgia, the Southeast, and the nation, conducting more than $1 billion in research annually for government, industry, and society. .
JOURNEYS
Cryosphere
DOI
RESEARCH METHODS
Simulation / computational modeling
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Sea water layer penetrates and melts under the underground ice layer
ARTICLE PUBLICATION DATE
February 8, 2022
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