Watching a glacier
NASA scientists are keeping sharp eyes on Greenland's glaciers. Such gazing reveals more than the beauty of this unique and massive, icy island. The scientists, part of NASA's Operation IceBridge, are conducting airborne surveys to find out how the glaciers are changing over time.
Glacier surface
Laser altimeters can map the teensy details of the surfaces of these Greenland glaciers. NASA uses two laser altimeters: One is optimized for low altitude and the other for medium altitude, they said.
Laser altimetry
The laser altimeter measurements show elevation changes on the glacier surface.
Helheim Glacier
"On Greenland’s rugged eastern coast, spilling into a mountainous fjord, lies the 4-mile-wide Helheim Glacier, named for the Viking world of the dead," NASA says in the video.
Dramatic chnages
"Flights spanning two decades reveal the dramatic changes that have taken place," NASA said on a video about the mission.
Rapid retreat
Here, the glacier is shown after a rapid retreat and thinning episode.
Partial recovery
Following the retreat, the glacier partially recovered its former extent.
Helheim in 2001
NASA missions have flown along the center line of the glacier year after year. Here, the extent of the Helheim Glacier is shown in 2001 from NASA Operation IceBridge surveys.
Helheim in 2007
The extent of the Helheim Glacier is shown in 2007 from NASA Operation IceBridge surveys.
Helheim extent
The extent of the Helheim Glacier is shown in 2011 from NASA Operation IceBridge surveys.
Helheim in 2014
The extent of the Helheim Glacier is shown in 2014 from NASA Operation IceBridge surveys.
