Predicting the movements of a giant GPS-tagged icebergMaritime Accidents, Oceanology, Safety and Security — By admin on November 22, 2013 at 12:09 PM
An iceberg from the Pine Island Glacier is about to receive a lot of attention.
A team of Earth systems scientists from the UK has been awarded an emergency £50, 000 ($80, 555) grant to track and predict the movements of a massive iceberg measuring 700 sq km (270 sq miles) that could be floating perilously in the direction of major shipping lanes.
The iceberg was part of the Pine Island Glacier, a large ice stream flowing into the Amundsen Sea, Antarctica. NASA first spotted a crack in the glacier that looked like the start of a giant berg in 2011, but it was not until July this year that it became clear that crack went all the way through.
“The iceberg remained attached to the glacier for four months [after this] because it had been winter in the southern hemisphere and the iceberg is likely to have been frozen against the glacier, ” Grant Bigg, a professor at the University of Sheffield leading the study, told Wired.co.uk. “We expected it to break-away but did not know when this would occur. From satellite images you couldn’t see much evidence of the split widening until November 11.”
Grant, along with a team at the University of Southampton, put in an application for the grant three weeks after the crack had gone all the way through. The grant has just been awarded it in the wake of those November 11 images showing that the gap has now widened to a few kilometers.
The iceberg has been splashed across headlines for its magnitude, slated as being eight times the size of Manhattan. But it is its unknown trajectory that has led to the grant being awarded so swiftly. An iceberg of this size can survive “for several years before it melts”, according to Bigg. And if currents take it too far in the wrong direction, it could pose a threat to the busy shipping lanes of the South Atlantic near South America.
“We know from previous giant icebergs and from preliminary modeling experiments, that this is a sensitive area of the Southern Ocean circulation where icebergs can either move westwards along the coast or loop out into the Southern Ocean and become entrained in the eastward flowing Circumpolar Current, ” Bigg explained. The Circumpolar Current flows clockwise from west to east around Antarctica. “The occasional large iceberg has entered the South Atlantic through Drake passage in this manner in the past. In the last few years there have been three serious incidents between icebergs and ships near Antarctica, in one case leading to a cruise ship sinking. The icebergs concerned came from different regions, but these occurrences show the risk.”
Whether it travels along the coast or moves northward to warmer waters (where it will melt faster), Bigg added to Sky.com: “if these events become more common, there will be a build-up of freshwater which could have lasting effects.”
Right now, it’s the iceberg’s size that makes it a unique threat and one to watch.
“With large icebergs there is always a tendency to break apart over time. Having such a large iceberg with the potential to produce a number of fragments, which will probably travel in generally the same direction means that a much wider region of ocean than just that occupied by the iceberg may have an ice hazard.”
Bigg and his team have six months to plot its trajectory and hope to have predictions that take us up to the end of 2014 by that time. A researcher at Sheffield University will track the iceberg everyday while a Southampton colleague runs simulations based on a model Bigg created. Imagery is provided by NASA’s Terra and Aqua satellites and the Synthetic Aperture Radar from the German Space Agency’s Terrasar-X satellite. This is consolidated using data from the Brigham Young University’s Antarctic Iceberg Tracking Database, which has comprehensive data going back to 1978. Data from two GPS devices attached to the iceberg by the British Antarctic Survey will be used as well.
“We will predict its movement by using a high-resolution ocean model, which has an iceberg model embedded within it, ” Bigg tells Wired.co.uk.
Moving at a predicted 10cm/s (more than 19.5 ft/m) speed, the monster of an iceberg obviously does not pose any imminent threat. And if it were to reach the shipping lanes, that’s a long while off. Once there, all we can do is issue hazard warnings to vessels passing through what is one of the world’s busiest shipping lanes at South America’s tip.
“This is a short-term event, and the survival time once it reaches as far north as the Southern Ocean shipping lanes will probably be at most a year, ” said Bigg.
This article originally appeared on Wired.co.uk.