NASA maps Greenland’s buried valleys from the ice surface above

Ridges and valleys subtly alter the surface and motion of the ice flowing over them; researchers can work backwards from those observations to estimate the terrain below. NASA’s September 28 visualization makes that inference legible at the scale of Greenland.

The underlying June 30 study mapped 1,943 valleys, roughly a third newly identified. Others run farther inland than earlier maps suggested. The discovery is geographic: these are old landforms newly connected on a map, rather than valleys that have just appeared. Their routes matter because valleys help channel ice towards the coast.

Read the image as a reconstruction. Its colours show estimated bed elevation in metres, including terrain below sea level. The four insets let you move between the island-wide network and individual features. Open the full map, choose one inset and follow a valley back into the wider landscape.

The strongest inference concerns where valleys run. Their absolute relief is less secure: the calculation simplifies how readily ice slides over the ground. Changing that assumption alters the estimated vertical shape. The resulting map improves the questions researchers can ask about the ice sheet, without supplying a new sea-level forecast.

For readers who work with geographic data, the study’s open archive offers an unusually accessible first step. The mapped valley vectors occupy about 1.1 MB; the reconstructed grid is about 4.1 GB. Begin with the small file and compare a route with the paper’s uncertainty discussion. A finer picture is most valuable when its limits become easier to see.