Greenland is a big island -- about the size of Saudi Arabia -- covered by ice and snow. But climate experts agree that frozen ground cover is melting at an accelerating pace, raising the sea level.
The rivers and streams that carry glacial meltwater across Greenland’s ice sheet are a beautiful shade of blue, but the water moves so fast and drains so unpredictably into moulins or sinkholes that researchers needed to use a range of high-tech instruments to get their measurements. (UCLA/Laurence C. Smith)
Meltwater drains from Greenland’s ice sheet at such a fast rate that researchers couldn’t risk entering the water to get readings so they used a remote-controlled drone boat. (UCLA/ Laurence C. Smith)
Researchers measured how fast water was flowing through rivers using an Acoustic Doppler Current Profiler. (UCLA/Laurence C. Smith)
To calculate river flow, researchers used autonomous GPS beacons, which drift down the river broadcasting its location and velocity to communications satellites. (UCLA/ Laurence C. Smith)