A team of twelve scientists and support staff has arrived on Pine Island Glacier in West Antarctica in the second stage of an ambitious research project to investigate why the glacier is retreating faster than any other in the world.
Funded by the Natural Environment Research Council, the iSTAR programme brings together leading scientists from eleven UK universities as well as from the British Antarctic Survey (BAS).
Dr Andy Smith from BAS says:
“This is our second season on the ice and we have an exciting challenge ahead. We are trying to find out how much ice is being lost into the ocean and what this means for future sea level rise. Satellite data can tell us a lot but we do need to use ocean measurements and ground-based technologies to get a clearer picture of what’s going on. We need to be able to be able to distinguish changes in ice density from changes in ice mass; and we need to understand how ice is affected by the motion of the underlying solid Earth beneath it.”
During the next 10 weeks the team will travel across the ice making a series of ice-based measurements as they go. Data captured using a neutron probe, ice core drilling and GPS measurements will help reconstruct the ‘missing’ data from two decades of satellite measurements.
These combined data will help unravel uncertainties in projections for the future sea level rise.
An advance party of field assistants and engineers arrived on location in October to dig out the tractors, caboose and other equipment. The area was covered by deep snow that had built up since last January after they had completed the first overland traverse. The tractors survived the harsh winter relatively unscathed due to the fact they were left parked on high berms (snow mounds).
Damon Davies, of the University of Edinburgh, will deploy a neutron probe to measure the density of the surface snow layers. He says:
“We will drill a series of 10 metre deep holes to lower the probe into. We will then measure the hydrogen content of the snow to get an idea of its density. Fast neutrons emitted from a radioactive source in the probe interact with the hydrogen atoms in the snow. The neutrons scatter as they bounce off the hydrogen and some are captured by the probe. “
Robert Mulvaney, from BAS, leads the team that will extract ten 50 metre ice cores. He says:
“When we analyse the particles and water content of these ice cores back in our Cambridge labs we will see the snow accumulation over the past one hundred years or so and get clues about the atmosphere at the time the snow fell.”
Alex Brisbourne and his team will capture seismic data at seven sites on the Glacier. This involves drilling holes into the ice which are then loaded with explosives. When these detonate, the echoes from below are recorded which give an indication of the bedrock directly under the ice.
GPS receivers that were installed last season along the glacier will be dug up and collected as the traverse revisits each site. These record signals from satellites and the data stored in them should be able to determine how much the glacier has moved over the twelve months.
Science leader Andy Smith says:
“It’s an exciting time for the iSTAR programme as a new team prepares to head south to Antarctica. For some of the team, it will be their first time on the continent. From a scientific point of view, it will be really interesting to see what readings we get from the twelve GPS stations we left on the glacier last year. This data will help us determine how fast the glacier is moving towards the sea.”
The mission is due to be completed in January 2015.