Author(s): Jinzhao Li; Qingkai Wang; Shijie Chen; Peng Lu
Linked Author(s): Peng Lu, Qingkai Wang
Keywords: Computed tomography; Arctic sea-ice; Bubble; 3D structure
Abstract: The microstructure of sea ice is a key basis for investigating its physical properties and dynamic processes, and precise quantification of the parameters of air-filled pores in ice is essential for retrieving more accurate atmospheric gas signals from ice cores in the future. Computed tomography (CT) has been demonstrated to be an effective technique for characterizing sea-ice microstructure, enabling analyses of the morphology of air pores in sea ice at spatial resolutions of several micrometres. In this study, ice cores collected at an Arctic ice station were analyzed. Physical measurements focused on characterizing the crystal structure and, based on measured physical properties, calculating the air volume fraction in ice at different temperatures, thereby providing constraints for subsequent core subdivision and threshold selection. Prior to the microstructural analysis, we reviewed scanner types, sample pretreatment procedures, and image segmentation and reconstruction strategies. A total of 297 slices were acquired, of which 254 were used for subsequent analysis. Combining the calculated air volume fractions with threshold-based segmentation, air pores were extracted from the CT images, yielding 5638 bubbles, for which a suite of two- and three-dimensional quantitative metrics was established. The results show that, at a given temperature, air pores in granular sea ice are on average larger than those in columnar sea ice, and that pore shapes are predominantly near-spherical. Across temperatures, with increasing temperature the number of pores decreases, while their characteristic size increases.
Year: 2026