Mapping Ice Flow in Antarctica

A recently released map of the speed and direction of ice flows across Antarctica not only reveals some previously undiscovered geographical features, but also suggests a new explanation for how ice moves across the continent. Researchers constructed the map after studying billions of data points taken from a number of polar-orbiting satellites. After accounting for cloud cover, solar glare, and various land features, the scientists were able to determine the shape and speed of glacial formations across Antarctica. They found that some formations moved as much as 800 feet per year, and they also discovered a previously unknown ridge that runs east-to-west across the continent. The NASA animation below shows the ice flow patterns. “This is like seeing a map of all the oceans’ currents for the first time,” says Eric Rignot of the University of California—Irvine, who led the study (subscription required for access to the full article). “It’s a game changer for glaciology.” The observations also showed that the ice moves by slipping and sliding along the land, and not by being crushed and broken down by ice above it, as had previously been theorized by many glaciologists. That difference is critical to forecasting sea level rise in decades to come since a loss of ice at the water’s edge means “we open the tap to massive amounts of ice in the interior,” according to Thomas Wagner of NASA’s cryospheric program.