02 August, 2019 by Nicholas O'Flaherty
A new map of Antarctic ice velocity by glaciologists from the University of California, Irvine and NASA’s Jet Propulsion Laboratory is the most precise ever created, constructed from 25 years' of satellite data. the map is 10 times more accurate than previous renditions, covering more than 80 percent of the continent.
To chart the movement of ice sheets across the surface of the enormous land mass, the researchers combined input from six satellite missions: the Canadian Space Agency’s Radarsat-1 and Radarsat-2; the European Space Agency’s Earth remote sensing satellites 1 and 2 and Envisat ASAR; and the Japan Aerospace Exploration Agency’s ALOS PALSAR-1.
Previous mapping efforts relied heavily on “feature” and “speckle tracking” methods, which detect the subtle motion of parcels of ice on the ground over time; this approach has been proven effective in estimating ice flow speed. To measure significantly slower ice sheet movement in the vast interior regions, the UCI team augmented these techniques with synthetic-aperture radar phase interferometry, which detects the subtle motion of natural reflectors of radar signals in snow/ice independent of the size of the parcel of ice illuminated by the radar.
For first time, high-precision mapping of the Antarctica interior areas has been accomplished. The map will help improve understanding of ice behavior under climate stress, as well as the projections of sea level rise.