Thinning the Greenland ice sheet – Is it affected by the shape of a glacier?

COLUMBIA, Md., December 17, 2020 / PRNewswire / – Scientists at the Universities Space Research Association and their colleagues at NASA, University of Texas and other groups have confirmed that the slope of the bedrock is under glaciers around the Greenland an ice sheet can disperse or stop the ice thinning further inland.

Glaciers are usually rivers of ice that flow over the seabed and drain into the ocean. They escape and become thin as the climate warms and this thinning spreads further inland towards the center of the ice sheet.

Recently, by studying the topography of 141 outdoor glaciers Greenland, scientists have gained a better understanding of which glaciers could have a significant impact on the contribution of the Greenland Ice Sheet to sea level rise in the coming decades. They found that steep bedrock properties, known as “knickpoints”, can effectively stop the spread of ice thinning. This often occurs in areas where the topography of the bed is mountainous. In contrast, in more temperate terrain areas where hilltops are less present or less steep, glaciers can spread ice thinning far into the interior, away from of the sea. The results were published in Geophysical Research Letters.

University Space Research Association Scientist Dr. Denis Felikson at NASA ‘s Godard Space Flight Center, and the study’ s lead author noted, “Several small glaciers flow over a calm landscape in Northwest Greenland that can allow ice thinning to spread to the center of the ice sheet. These glaciers may have such a large role to play, that little attention has been paid to future sea level rise than the most famous and studied glaciers. ”

Glaciers that are flowing have a gradual glacier that flows through a calm landscape, or have no knocking place at all. There is interest in such glaciers, and they are concerned that, despite their size, their potential to allow thinning extends hundreds of kilometers inland, eroding the heart of the ice sheet.

Researchers have concluded that by allowing the thinning of ice sheets to spread far into the country, these smaller glaciers will provide no knick points on the ice sheet. continue to lose ice over a longer period than the larger glaciers flowing on sub-rock with hilly points.

“It is only recently that scientists have been able to identify the steep changes in topography using digital elevation models to shape a landscape beneath the ice. Without that ability , the research team would not have been able to find the conclusions, “Felikson said. The bed-shaped digital elevation model, called Dataset BedMachine – a high-resolution model of the bed under the Greenland ice sheet – surrounded by using aerial data from NASA’s Operation IceBridge, was crucial for this research.

Using NASA’s remote sensing data, scientists were able to determine if the thinning of the ice sheet could continue upstream from the glacial ocean boundary by computing one meter based on the shape of the ice sheet. glacier at all points on glacier flow line. This helped them to identify a resting place between glacial ice up and down the river. “Ice below the hilly area tends to thin out from the edge of the glacier. But thinning does not extend upstream and therefore has no effect on the interior of an ice sheet. means that some parts of the Greenland ice sheet are more sensitive to what happens at the periphery than other parts, “says Felikson.

“Glaciers can be influential in raising sea levels, not because they are large and dense, but because they have access to more ice and can eat away,” Felikson said. “It will take them a long time to respond, but over the long term they can make a significant contribution to sea level rise, just as the large glaciers do.

According to Felikson, “We are looking for evidence from models for the theoretical limitations on attenuation we have found, and we hope that future modeling efforts will further test how ice thinning spreads on ice -stream. ”

This research was funded by NASA under a grant from NNX12AP50G and by the Gale White Fellowship at University of Texas Institute for Geophysics.

Related resources:

Paper link:

BedMachine Database Link: BedMachine v3: Complete bed landscape and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mass retention, Geophysical Research Letters. 44 ..

IceBridge BedMachine Greenland, Version 3. Boulder, Colorado USA. NASA National Snow and Ice Data Center Surrounded Active Archive Center. doi:

About USRA
The Universities Space Research Association is a nonprofit research organization where the combined efforts of in-house talent and university-based knowledge come together to advance space science and technology. USRA works across disciplines including biomedicine, planetary science, astronomy, and engineering and weaves these capabilities into applications from fundamental research to resource management and operations. USRA engages in the creativity and authoritative knowledge of the research community to provide innovative, proactive solutions to Federal agencies and other government supporters.

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