NASA’s ICESat satellites have observed ice sheet losses in Greenland and Antarctica, pushing up sea levels by 14mm since 2003.
The study using ICESat and ICESat-2, which launched in 2018, have found that Greenland’s ice sheets lost on average 200 gigatons of ice per year and Antarctica lost 118 gigatons a year. A laser altimeter sent pulses of light to Earth’s surface and measured how long it took to return to the satellite. Pulse rates allow for a dense map of measurement over the ice sheet, with scientists determining how much the ice sheets changed over a year.
Researchers took tracks of earlier ICESat measurements and overlaid the tracks of ICESat-2 from 2019, and took data from sites where the two datasets overlapped. To calculate how much ice was lost, they developed a model to convert volume change to mass change by calculating densities across the ice sheets to allow the total mass loss to be measured.
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