Snowdrift and Accumulation on Landfast Ice Around Antarctic Icebergs: Insights from Modeling and Observational Data

Océane Hames , Iolène Bouzdine, Veit Helm, Christian Haas, Michael Lehning

Snow cover influences sea ice thermodynamics and mass balance, making its distribution and properties critical to polar research. Grounded icebergs in coastal Antarctica substantially affect surface snow distribution and landfast sea ice patterns, which has received limited scientific attention. To address this gap, this study integrates observational data with numerical snow transport simulations to investigate snow distribution on landfast ice around icebergs, emphasizing the influence of wind and iceberg size. Observations show that persistent wind directions shape characteristic snow patterns around icebergs, with substantial windward and lateral drifts and an elongated snow-depleted region in the lee. They also indicate that snowdrift size scales non-linearly with iceberg size, demonstrating reduced snow accumulation efficiency for larger icebergs. This trend is partially captured by the model, which also highlights the key role of wind direction shifts in reproducing observed distributions. The model further suggests that the maximum extent of snowdrifts is constrained by peak wind speeds encountered on site. Together, our findings reveal emerging links between ice shelf and fast ice processes, the use of iceberg-associated snowdrifts as proxies for local weather, and insights into the snow mass balance on Antarctic landfast ice.