Bringing a 3-D perspective to Greenland’s ice
A detailed picture of Greenland’s largest, fastest-moving glacier and its long-term behavior has arisen from a three-dimensional rendering of more than 60 years of data. The analysis, led by Beata Csatho (University at Buffalo), was funded by NSF and NASA and published online in February in the Journal of Glaciology.
Csatho and colleagues focused on Jakobshavn Isbrae, a glacier measuring about 6 kilometers (4 miles) wide. During the past decade, Jakobshavn Isbrae has begun to experience rapid thinning and doubling of the amount of ice it discharges into Disko Bay. To document the history of Jakobshavn Isbrae, Csatho and her colleagues combined field mapping, remote sensing, and satellite imaging, as well as digital techniques that allowed the team to glean data from aerial photographs up to 60 years old. The result was a 3-D mosaic constructed from many 2-D data sets.
“By reprocessing data contained in these old photographs and records, we have been able to construct a long-term record of the behavior of the glacier,” says Csatho. “This was the first time that the data from the 1940s could be reused in a coherent way.”
The research demonstrates how remote sensing and digital imaging techniques can produce rich data sets and new insight. For example, conventional methods of assessing change in glaciers have depended on documenting iceberg calving, in which large pieces at the front of the glacier break off. “But we found that you can get significant changes in the ice sheet without seeing a change in front,” Csatho says.
The study has implications for the future of Greenland’s ice. “Although the thinning started as early as the end of the 18th century, the changes we are seeing now are bigger than can be accounted for by normal, annual perturbations in climate,” Csatho says. If current climate models were to include data from ice dynamics in Greenland, she notes, the sea level rise by 2100 could be substantially higher than recent projections indicate.
University at Buffalo, State University of New York
University of Kansas
Ohio State University