Researchers from the University of California, Irvine and NASA’s Jet Propulsion Laboratory have identified stormlike circulation patterns beneath Antarctic ice shelves that are accelerating melting, a process with significant implications for global sea level rise.
The study, published in Nature Geoscience, is the first to examine ocean-induced ice shelf melting on a timescale of days rather than months or years. This approach allowed researchers to link “ocean storm” activity directly to intense melting at Thwaites Glacier and Pine Island Glacier in West Antarctica’s Amundsen Sea Embayment.
Using climate simulation models and moored observation tools, the team was able to observe submesoscale ocean features—ranging from 1 to 10 kilometers across—with a resolution of 200 meters. These small-scale phenomena were found to be important drivers of warm water intrusion beneath ice shelves.
“In the same way hurricanes and other large storms threaten vulnerable coastal regions around the world, submesoscale features in the open ocean propagate toward ice shelves to cause substantial damage,” said lead author Mattia Poinelli, a UC Irvine postdoctoral scholar in Earth system science and NASA JPL research affiliate. “Submesoscales cause warm water to intrude into cavities beneath the ice, melting them from below. The processes are ubiquitous year-round in the Amundsen Sea Embayment and represent a key contributor to submarine melting.”
Poinelli explained that their research revealed a feedback loop: more ice shelf melting increases ocean turbulence, which then leads to further melting. “Submesoscale activity within the ice cavity serves both as a cause and a consequence of submarine melting,” he said. “The melting creates unstable meltwater fronts that intensify these stormlike ocean features, which then drive even more melting through upward vertical heat fluxes.”
According to their findings, these high-frequency processes account for nearly one-fifth of total submarine melt variance over an entire seasonal cycle. During extreme events, submarine melting can triple within hours when these features interact with ice fronts.
Observational data from moorings near the glaciers support these results by showing similar warming and increased salinity at depths corresponding with periods of rapid melt described in the study.
“The region between the Crosson and Thwaites ice shelves is a submesoscale hot spot,” Poinelli noted. “The floating tongue of the Thwaites ice shelf and the shallow seafloor act as a topographic barrier that enhances submesoscale activity, making this area particularly vulnerable.”
These findings raise concerns given ongoing climate change. If West Antarctica’s Ice Sheet collapses entirely, it could raise global sea levels by up to three meters. The research suggests that warmer waters and longer periods without sea ice could make energetic submesoscale fronts even more common in future scenarios.
“These findings demonstrate that fine oceanic features at the submesoscale – despite being largely overlooked in the context of ice-ocean interactions – are among the primary drivers of ice loss,” Poinelli said. “This underscores the necessity to incorporate these short-term, ‘weatherlike’ processes into climate models for more comprehensive and accurate projections of sea level rise.”
Co-author Yoshihiro Nakayama from Dartmouth added: “Initially, I was just trying to understand the observations using model output so we can say, ‘This is how you explain the data.’ But now that our model matches the data so well, we can go an extra step. We can extrapolate further to say there’s weatherlike storms hitting and melting the ice.”
Eric Rignot, UC Irvine professor who advised on polar studies for this project stated: “This study and its findings highlight the urgent need to fund and develop better observation tools, including advanced oceangoing robots that are capable of measuring suboceanic processes and associated dynamics.”
Lia Siegelman from Scripps Institution of Oceanography also contributed as co-author. Funding came from NASA’s Cryospheric Sciences Program with additional support from NASA Advanced Supercomputing Division.
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