Observation of wave propagation over 1,000 km into Antarctica winter pack ice

A drifting wave-ice buoy (Medusa-766) was deployed at the Lutzow-Holm Bay (LHB) marginal ice zone in Antarctica during the 63rd Japanese Antarctic Research Expedition to study the wave influence on the unstable LHB fast ice. Medusa-766 survived the Antarctic winter as it was located deep in the ice cover with the shortest distance to the ice-free Southern Ocean over 1,000 km; at this time, there was evidence of 8-cm-height wave signal at the buoy position. Using the the ECMWF's reanalysis wave data, we show that the incoming waves were likely 4-m waves that were generated by an extratropical cyclone in the Southern Ocean. Wave-induced ice breakup potential for this event could extend hundreds of kilometres into the ice field. When Medusa-766 was in LHB in the summer months, it did not detect sizable wave energy despite the low sea ice concentration extent even during on-ice wave events. Understanding the wave attenuation characteristics is needed to elucidate the ocean wave effect to the unstable LHB fast ice. The success of Medusa-766 demonstrates the robustness of the general design and the high sensitivity of the sensor used, which is promising for future LHB wave-ice interaction research.

Automated summary

A drifting wave-ice buoy (Medusa-766) was deployed in the Lutzow-Holm Bay in Antarctica to study the wave influence on the unstable fast ice. The buoy survived the Antarctic winter and detected evidence of wave signals, which were likely generated by an extratropical cyclone in the Southern Ocean. Wave-induced ice breakup potential was found to extend hundreds of kilometers into the ice field. However, during the summer months, the buoy did not detect significant wave energy, even during on-ice wave events.