New data from space is providing the most precise picture yet of Antarctica’s ice, where it is accumulating most quickly and disappearing at the fastest rate, and how the changes could contribute to rising sea levels.
The information, in a paper published on Thursday in the journal Science, will help researchers better understand the largest driver of ice loss in Antarctica, the thinning of floating ice shelves that allows more ice to flow from the interior to the ocean, and how that will contribute to rising sea levels. Researchers have known for a long time that, while the continent is losing mass over all as the climate changes, the change is uneven. It is gaining more ice in some areas, like parts of East Antarctica, and losing it quickly in others, in West Antarctica and the Antarctic Peninsula.
Helen A. Fricker, an author of the paper, said that scientists have tried to study the link between thinning shelves and what is called grounded ice, but have been hampered because most observations were of one area or the other, and made at different times. “Now we’ve got it all on the same map, which is a really powerful thing,” said Dr. Fricker, a glaciologist at the Scripps Institution of Oceanography in La Jolla, Calif.
The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, was launched in 2018 as part of NASA’s Earth Observing System. It replaced a satellite that had provided data from 2003 to 2009. ICESat-2 uses a laser altimeter, which fires pulses of photons split into six beams toward the Earth’s surface 300 miles below. Of the trillions of photons in each pulse, only a handful of reflected ones are detected back at the satellite. Extremely precise measurement of these photons’ travel times provides surface elevation data that is accurate to within a few inches.
“It’s not like any instrument that we’ve had in space before,” said another of the authors, Alex S. Gardner, a glaciologist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. The resolution is so high that it can detect rifts and other small features of the ice surface, he said.The New Times