PHEW, we just come back after the second 12 hour shift of ice thickness measurements. Why is this marathon really necessary?
The tip of an ice berg shows only 10% of its entire thickness. This means that an ice berg with 10m above the ocean has a 90m keel below the surface.
We can apply this principal to floating ice shelves and simply measure the surface elevation to invert it for ice shelf thickness. However, close to the grounding line, where we are, the ice shelf is still influenced by the Darwin Glacier. Here the ice is not freely floating and we cannot apply the ice berg principle. Consequently we take our rustic wooden sledge for a drive and measure the ice thickness with radar. This takes a long time, as the ice surface is very rough.