Belissima

Follow the sequel of the first scientific Belgian Antarctic Research Expedition to the Princess Elisabeth Station in Antarctica. This is the BELISSIMA project (BELgium Ice-Sheet /Shelf-Ice Measurements in Antarctica).

From 16 November to 22 December 2010 we'll head south to the vicinity of the new Belgian Antarctic research station to pursue glaciological investigations of the transition between the ice sheet and the ice shelf, the so-called grounding line. This will help us to better understand the current mass balance of the Antarctic ice sheet.

Expedition members

The expedition members are Frank Pattyn (ULB), Jean-Louis Tison (ULB), Thierry Boereboom (ULB), Marie Dierckx (ULB), Bryn Hubbard (University of Aberysthwyth), and Kenny Matsuoka (Norwegian Polar Institute).

Frank	Jean-Louis	Thierry	Marie	Bryn	Kenny

What is a grounding line and why is the transition zone so important?

A grounding line is the point where the ice sheet - which has been resting on bedrock, arrives at the ocean and starts to float. The part resting on bedrock is the ice sheet and the floating part is an ice shelf. The limit between the two of them is the grounding line. So basically whenever ice passes the grounding line, it becomes part of the ocean and has the potential to raise sea level.

But of course this grounding line is not static. It can move. If an ice sheet becomes bigger it expands horizontally and the grounding line moves forward, the result is that there will be more ice stored on the bedrock and less ice in the ocean, so you get a lowering of sea level. But if a grounding line retreats, it means more ice becomes part of the ocean, and sea level rises.


BELISSIMA aims at measuring the interaction between the ice sheet, the ice shelf, and the ocean at the grounding line. For this, we take a highly multi-disciplinary approach with the goal of using all the information we could obtain. Radar specialists measure the ice thickness and analyze the magnitude of reflection to see what kind of substrate lie underneath the ice sheet - whether it is frozen to the bed, or whether it is resting on wet sediment and thus in contact with the ocean. With radar, we are also able to visualize internal layering of the ice sheet, which is fantastic for ice sheet modelling because that's really a way of better constraining the ice sheet models. These internal layers, more or less parallel to the surface of the ice sheet, are seen as isochrones (layers of ice from the same time period), which enables us to examine whether any rapid changes have occurred in the past, or whether there are any changes in the accumulation pattern.

But we also drill through the ice shelf into what is called marine ice. In the ocean near the grounding line, you have cases of ocean currents driven by thermohaline circulation coming from deep in the ocean, which has the possible effect of melting the base of the ice shelf and making the grounding line retreat. But this oceanic water also refreezes underneath the ice shelf further away from the grounding line. As far as we know today, this marine based ice might stabilize, destabilize, enhance, or just retain the flow of ice shelves at their current rate. Anything is possible, which is why drilling into them and retrieving samples is very important.