COLUMBUS, Ohio – Antarctic ice is melting, adding a lot of water to the world’s oceans and causing them to rise – but that melting is not as linear and consistent as scientists previously thought, a new study on 20 years worth of satellite data appearing. .
The analysis, built on gravity field data from NASA’s satellite system, shows that Antarctica ice melts at different rates each year, suggesting that the models used by scientists could to predict future sea level rise as well.
“The ice sheet is not changing with a steady rate – it is more complex than linear change,” said Lei Wang, assistant professor of civil, environmental and geological engineering at Ohio State University and lead author of the study. “The change is more dynamic: The speed of melting varies with time.”
The research was published in Geophysical Research Letters and was presented at the fall meeting of the American Geophysical Union in December.
The researchers ’analysis is built on data from NASA’s GRACE (Gravity Recovery and Climate Experiment), a two-satellite mission that measures changes in the world’s oceans, groundwater and ice sheets.
Models predicting sea level rise are usually built around the assumption that ice is melting from the largest ice fields in the world in Antarctica and Greenland at consistent rate.
But this analysis found that, since the mass of ice on the Antarctic ice sheet varies by season and year, these projections are not as reliable as they could be. One year of heavy snowfall, for example, could lead to more ice in Antarctica. Changes in the atmosphere or the surrounding ocean could go down another year.
Overall, Wang said, the ice rate in Antarctica is declining. But a chart of the decline on a line graph would have spikes and valleys depending on what happened in a given time.
To understand these changes, Wang and the other researchers evaluated data on the area of gravity between the satellites across Antarctica and ice on the continent. Changes in ice mass – either rising from large snowfalls or decreasing from melting – change that area of gravity.
From 2016 to 2018, for example, the ice sheet in West Antarctica grew slightly due to heavy snow. At the same time, however, the ice sheet in East Antarctica shifted due to melting.
“I’m not saying that melting Antarctica ice isn’t a real problem – it’s still very hungry,” Wang said. “All of Antarctica is losing mass, very fast. It’s just a time-scale problem and a rate problem, and our models that predict sea level change should to show that. ”
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Ian Howat, director of the Ohio State Polar and Climate Center for Polarization, worked on this analysis.
The work was funded by NASA.
INFORMATION:
Lei Wang,
[email protected]
Written by Laura Arenschield,
[email protected]
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