Characterizing Nearshore Icebergs in front of the Dalk Glacier, East Antarctica by UAV Observation

Abstract. Icebergs are the products of glacier calving, and they float on the ocean, influencing ocean circulation and maritime activities. Extensive research has been carried out on the distribution and shapes of icebergs. However, current research mainly focuses on medium and large icebergs. Smaller icebergs, though numerous, are less studied due to the difficulty of detecting them in satellite imagery. In our research, high-resolution images obtained by an Unmanned Aerial Vehicle (UAV) during the Chinese 36th Antarctic expedition were used for the study of smaller icebergs. We extracted nearshore icebergs in front of Dalk Glacier using a method combining superpixel segmentation and Random Forest classification. We directly calculated the area and freeboard of these icebergs by combining Digital Surface Model (DSM) and further calculated their volume. Our research found that DSM generated without control points exhibit a dome effect, and fitting with a surface effectively mitigates this error. Our research identified 187 icebergs, whose area follows a power law distribution with a slope of -1.13. The area/volume relationships obtained from the UAV survey align surprisingly well with existing iceberg parameterization in large-scale ocean models, which was firstly proved to also be valid in growler and berg bit scale by observation evidence. Our research provides new data and insights into the distribution and geometry of small icebergs. Our research reveals the capability of UAVs in extracting iceberg geometric features, highlighting their advantages and discussing the potential and challenges of using UAVs in polar iceberg research.