Slice in the ice: Nasa creates incredible video 'fly-through' of 18-mile crack in Pine Island glacier from 3D laser scans



In October 2011, airborne Nasa researchers made the first-ever detailed 3D measurements of a major iceberg calving event - a new iceberg 'being born'.

The IceBridge team has now used the measurements - captured with a 3D laser imaging device - to create a 3D model of the crack in Pine Island Glacier, and an incredible video of what it would be like to fly through.



The animation was created by draping aerial photographs from the Digital Mapping System - a still camera with very precise geolocation ability¿over data from the Airborne Topographic Mapper - a scanning laser altimeter that measures changes in the surface elevation of the ice

The animation was created by draping aerial photographs from the Digital Mapping System - a still camera with very precise geolocation ability—over data from the Airborne Topographic Mapper - a scanning laser altimeter that measures changes in the surface elevation of the ice.

Both instruments were flown on NASA's DC-8 research airplane, and the data was collected on October 26, 2011.

The crack formed in the ice shelf that extends from one of West Antarctica’s fastest-moving glaciers.



The path of the crack in the animation stretches roughly 18 miles in length , with an average width of 240 feet.



The canyon ranged from 165 to 190 feet deep with the floor being roughly at the water line of the Amundsen Sea.



Split: This photograph from October 2011 shows the crack sweeping across Pine Island Glacier

Close-up: NASA has been monitoring the crack, which could be the first time scientists can see the birth of a huge iceberg

Scientists have been waiting for the crack to propagate through the rest of the ice shelf and release an iceberg, which they estimate could span 300 to 350 square miles.



Pine Island Glacier last calved a significant iceberg in 2001, and some scientists have speculated recently that it was primed to calve again.



But until an Oct. 14 IceBridge flight of NASA's DC-8, no one had seen any evidence of the ice shelf beginning to break apart. Satellite imagery seems to show the first signs of the crack in early October.

Pine Island has scientists' attention because it is both big and unstable – scientists call it the largest source of uncertainty in global sea level rise projections. But the calving underway is part of a natural process, NASA says.

Detection: Scientists were in the right place at the right time when they discovered the crack by flying over it in a DC-8 plane

The scientists say that no one has ever flown a 3D imaging tool over an iceberg of such a size as it's born

The team diverted their DC-8 back over the glacier for a return scannng mission.

The IceBridge team observed the rift running across the ice shelf for about 18 miles. The Airborne Topographic Mapper makes its precision topography maps with a laser than scans 360 degrees 20 times per second, while firing 3,000 laser pulses per second.



When flying at an altitude of 3,000 feet, as during this flight, it measures a swath of the surface about 1,500 feet wide. The rift is 250 feet wide along most of its length - so the veteran DC-8 pilot had a tricky job to keep the plane straigth along the rift.



It is likely that once the iceberg floats away, the leading edge of the ice shelf will have receded farther than at any time since its location was first recorded in the 1940s.



'A lot of times when you’re in science, you don’t get a chance to catch the big stories as they happen because you’re not there at the right place at the right time,' said John Sonntag, Instrument Team Lead for Operation IceBridge, based at Goddard Space Flight Center. 'But this time we were.'









