The observations confirm model predictions of sea level change from Greenland melting

Sea-level rise from melting glaciers and ice sheets poses an increasing threat to coastal communities around the world. A new analysis of high-resolution satellite observations takes a major step toward assessing this risk by validating theoretical predictions of sea-level change and computational models used to predict climate change-related impacts.

“Our method, which uses observations of sea surface height from satellites, independently verifies observations of Arctic and Greenland ice mass loss and allows us to distinguish global-scale contributions. sea ​​level It originates from separate ice sheets and glacier systems,” he said. fluid dynamics and geophysics at Los Alamos National Laboratory. Coulson is the lead author of an article in the journal Science On the discovery of the “fingerprint” of sea level change associated with the melting of the Greenland ice sheet. “Accurate prediction of regional patterns of sea-level change is absolutely fundamental to understanding the impacts of future climate change and predicting threats.”

Theoretical models and computer simulations can predict sea level changes due to the melting of ice sheets and glaciers.

“As this melting continues and water is redistributed around the global oceans, sea levels are not rising evenly,” Coulson said. “And because 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 unambiguously detected.”

Coulson’s search focused on satellite observations of sea surface height in the oceans surrounding the Greenland 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 gravity on the water in the open ocean, and so the water moves away from the sea. ice sheet. This causes sea level to fall near Greenland, but sea level rises to increasingly higher levels outside the region.

“We used new estimates of ice melt in the area to predict what the pattern of sea level change around Greenland would be,” Coulson said. “When we later compared this pattern to satellite observations of sea-level change, the match was remarkable. When the team saw this, it was an incredible eureka moment for us – ‘there it is, the sea-level fingerprint!’

Detecting the patterns has historically been hampered by lack of measurements of sea surface height around polar ice sheets and the variability of shorter-scale processes such as changing currents and ocean density. On the research team Science benefited from the development of the paper satellite observations extends to higher latitudes than previously possible where the fingerprint signal is largest. The team processed it satellite data using a powerful new technique to remove variability due to ocean dynamics.

A new study confirms the accuracy of geophysical predictions sea ​​level change and adds confidence to projections of sea-level rise over the coming decades and centuries. As Coulson says, “This is a powerful and sensitive approach to monitoring ice sheets and glaciers in our warming world.”