Coastal sea ice thickness in Antarctica from airborne measurements

Abstract

Cryospheric, oceanic and atmospheric processes along the Antarctic coast find their expression in the sea-ice mass balance along the continental shelf. The sea ice thickness in this area and its dynamics is particularly hard to assess because of both its spatial and temporal heterogeneity and the logistical constraints for in-situ observations. In this contribution we provide an overview and results of our airborne observations of ice thickness and snow in the western Ross Sea, including our newest observations along the far East-Antarctic coastline. By conducting six airborne geophysical sea ice campaigns between 2009 and 2023, we obtained unique insights in ice-ocean-atmosphere processes in this important region of sea-ice formation. It includes; characteristic sea-ice processes as a result of the regular occurrence of coastal polynyas, such as the Ross Sea, McMurdo Sound, and Terra Nova Bay polynyas; processes as a result of the outflow of ice shelf water, which finds its expression in the formation of a sub-ice platelet layer under persistent fast ice.

Our main instruments are (i) an airborne electromagnetic induction (AEM) device and (ii) an airborne snow radar. In one season we were able to trial co-incident measurements with both instruments. The most representative flights have been achieved using a Basler BT-67 and Twin Otter fixed wing aircraft, whereas helicopter flights were restricted to land-fast sea ice.

We present our strategy to combine these measurements with satellite information, and how it contributes to a better understanding of the coastal Antarctic cryosphere as a whole