Aleksandra K. Mazur, Anna K. Wåhlin, Sebastiaan Swart

Icebergs have a significant influence on local and potentially global climate by altering ocean and sea ice environments. An object-based method for automatic iceberg detection has been applied to 2442 SAR images acquired during all seasons between 2006-2012 in the Amundsen Sea Embayment (ASE), Antarctica. During this period a total count of icebergs and their surface area were calculated in different seasons and months. There is a clear seasonal variability in icebergs number and surface area in the ASE. The highest values of both parameters are observed during austral winter, the lowest during austral summer. The changes concern mostly the icebergs smaller than 2 km2 and pertain to the area north of the Pine Island Bay. A general westward drift of icebergs was observed in the ASE shelf area. The drift patterns and the seasonal variation of the distribution indicate that the drift of icebergs in the northern part of the ASE is strongly modulated by sea ice. They indicate mostly allochtonous origin of those bergs (icebergs imported from the Bellingshausen Sea represent about 25-35% of the total surface area of mobile icebergs in the Amundsen Sea). This is a new result not previously studied in the literature.