New mapping method reveals 1,943 valleys beneath Greenland ice

NASA researchers used a new mapping method to trace 1,943 valleys beneath the Greenland Ice Sheet, about a third of them newly identified. The resulting map shows that roughly half the valleys recorded in an existing terrain dataset extend farther inland than previously mapped, sometimes by hundreds of kilometers. The method reads small changes in the ice surface measured by satellites to infer the shape of the bedrock below. More accurate terrain data could help scientists refine projections of how the ice sheet will flow as it retreats. The researchers mapped the valleys manually; the work has yet to be incorporated into a future version of the existing terrain dataset.