“With sufficient planning, you can almost eliminate adventure from an expedition.”
-Roald Amundsen, 1911, the first to reach the South Pole.
The area where ice gets in direct contact with the ocean water is called the grounding line. It is an important boundary for Antarctica, as this is where the predicted warming of the ocean will first impact the ice sheets. Processes here not only drive the rate of ice melt, they directly control the glacier dynamics. One such process is how tides influence the flow-speed of glaciers that feed into the ocean. Observations all around Antarctica show that glaciers speed-up drastically during large tides, but seem to slow down again when tides are only small. But the reason why this is happening is still at the heart of an ongoing debate across the science community…
We will measure changes in ice-flow velocity due to ocean tides at the Priestley Glacier near Jang Bogo station. Understanding the short-term influence of the ocean on ice-discharge from the continent is important to predict the long-time contribution of Antarctica to global sea-level rise. For this we deploy a state-of-the-art radar system on top of a mountain ridge and monitor the glacier’s response over a full spring-neap tidal cycle (14 days). We are also setting up GPS receivers and other high-precision instruments on the glacier’s surface to complement our radar measurements. A dense grid of ice-thickness measurements from a helicopter will be conducted by our South Korean friends. We use the Priestley Glacier as a case study, to better understand the processes in other, more inaccessible areas of Antarctica, where climate change already impacts the ice-sheets.