Giant Iceberg in the Making

Wed, 05/07/2017

All eyes are on Antarctica’s Larsen C ice shelf as a deep crack continues to cut across the ice, leaving  a huge chunk clinging on by a mere thread. When it eventually gives way, one of the largest icebergs on record will be set adrift.  Even before the inevitable happens, the European Space Agency's CryoSat mission can reveal some of the future berg’s vital statistics.

Monitored by the Copernicus Sentinel-1 radar mission, the crack in the ice is now around 200 km long, leaving just 5 km between the end of the fissure and the ocean. While we wait for Sentinel-1 to tell us when this 6600 sq km iceberg is spawned, CryoSat can reveal what the berg’s measurements will be. 

This Earth Explorer satellite carries a radar altimeter to measure the height of the ice surface. In general, this information is used to work out how the thickness of sea ice and land ice is changing and, consequently, how the volume of Earth’s ice is being affected by the climate.

“Using information from CryoSat, we have mapped the elevation of the ice above the ocean’s surface and worked out that the eventual iceberg will be about 190 m thick and contain about 1155 cubic kilometres of ice.  We have also estimated that the draft – meaning the iceberg’s depth below sea level – could be as much as 210 m.   We will continue to use CryoSat to monitor how the berg changes as it drifts away from the ice shelf.”

 -   Dr Noel Gourmelen, School of GeoSciences, University of Edinburgh

Icebergs calve from Antarctica all the time, but because this one is particularly large, its path across the ocean needs to be monitored as it could pose a hazard to maritime traffic.  Again the Sentinel-1 and CryoSat missions will play an important role in tracking the berg and keeping an eye on how it changes.

A berg, similar in size, drifted around the Brunt ice shelf in December 2015, causing alarm for those stationed at the Halley research base, which is sited on the floating section of the shelf.

The CryoSat Mission 

ESA’s CryoSat mission manager, Tommaso Parrinello, said,

“The main purpose of CryoSat is to give us information to understand how ice is changing to improve our understanding of Earth. The value of having satellites built to deliver for science and missions like Sentinel-1, which are built to deliver for everyday applications, is enormous.   In this particular case, we see how the Copernicus Sentinel-1 mission and the ESA Earth Explorer CryoSat mission complement each other giving us a powerful tool to monitor changing ice sheets.”

 

Further Information

European Space Agency: CryoSat Mission 

School of GeoSciences, Dr Noel Gourmelen: Profile

Larsen C Iceberg, N Gourmelen
Larsen C Iceberg, N Gourmelen