Accurate predictions of regional sea level changes are essential to understand the impact of climate change on coastal areas
Rising sea levels from melting glaciers and ice caps pose an increasing threat to coastal communities worldwide. A new analysis of high-resolution satellite observations takes a major step forward in assessing this risk by confirming theoretical predictions and computational models of sea level changes used to predict climate change-induced impacts.
“Using sea-surface elevation observations from satellites, as we have done, independently verifies observations of the loss of ice masses in the Arctic and Greenland, and allows us to elucidate contributions to global sea-level rise from individual ice sheets and glacier systems.” together,” said Sophie Coulson, a postdoctoral researcher in fluid dynamics and geophysics at Los Alamos National Laboratory. Coulson is lead author of a article in the journal Science on detecting the “fingerprint” of sea level changes attributable to the melting of the Greenland ice sheet. “Predicting regional patterns of sea level change accurately is absolutely essential to understanding the impacts of future climate change and predicting hazards.”
Theoretical models and computer simulations can predict sea level changes as ice sheets and glaciers melt.
“As this melting continues and the water is redistributed across the oceans, sea levels are not rising evenly,” Coulson said. “And since each glacier and ice sheet has a unique pattern of sea-level change, these patterns have come to be known as sea-level fingerprints. But despite more than half a century of research, these fingerprints have never been unequivocally detected.”
As ice sheets and glaciers in Greenland melt and water is redistributed across the world’s oceans, sea levels are not rising evenly. New research using satellite measurements at high latitudes confirms computer models predicting lower sea levels around Greenland, but higher levels further away. Credit: Matthew Hoffman, Courtesy of loose Alamos National Laboratory
Three decades of observations
Coulson’s search focused on satellite observations of the height of the sea surface in the oceans around the Greenlandic Ice Sheet over the past three decades. The dominant effect in this region is that as the Greenland ice sheet loses mass, it exerts less attraction for water in the open ocean and thus water migrates away from the ice sheet. This results in a lowering of the sea level near Greenland, but a gradually higher sea level rise outside the region.
“We predicted what the pattern of sea level change around Greenland would be using new estimates of ice melting in the area. Then when we compared this pattern to satellite observations of sea level change, the fit was remarkable. It was an incredible eureka moment.” for us when the team saw it – “There it is, the sea level fingerprint!”
Detection of the patterns has been hampered in the past by the lack of sea surface height measurements around polar ice sheets and the variability of shorter timescale processes, such as changing currents and ocean density. The Science paper’s research team used processed satellite observations that extend to much higher latitudes than previously possible, where the fingerprint signal is greatest. The team processed this satellite data using a powerful new technique to remove the variability due to ocean dynamics.
The new study confirms the accuracy of geophysical predictions of sea level change and adds confidence to projections of sea level rise over the coming decades and century. As Coulson said, “It’s a powerful and sensitive approach to monitoring ice sheets and glaciers in our warming world.”
Rising sea levels from melting glaciers and ice caps pose an increasing threat to coastal communities worldwide. A new analysis of high-resolution satellite observations takes a major step forward in assessing this risk by confirming theoretical predictions and computational models of sea level changes used to predict climate change-induced impacts. LA-UR-22-30055
Paper: “A sea level fingerprint detection of the Greenland ice sheet melt,by Sophie Coulson (T-3), Sönke Dangendorf, Jerry X. Mitrovica, Mark E. Tamisiea, Linda Pan, and David T. Sandwell, in Science. DOI: 10.1126/science.abo0926
Financing: Sophie Coulson’s work on this research was supported by a Postdoctoral Fellowship from a Los Alamos National Laboratory Director
Thanks to Los Alamos National Laboratory
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