Seasonal evolution of granular and columnar sea ice pore microstructure and pore network connectivity

• Published in: Journal of Glaciology
• Main Authors: Marc Oggier, Hajo Eicken
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2022
• Subjects: Frazil ice; ice core; ice crystal studies; ice physics; sea ice; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Arctic; Journal of Glaciology; Sea ice; Alaska
• Online Access: https://doi.org/10.1017/jog.2022.1; https://doaj.org/article/074bf2d4ab9d4bdbacb0b3e7d4b2d0cf

Sea-ice pore microstructure constrains ice transport properties, affecting fluid flow relevant to oil-in-ice transport and biogeochemical processes. Motivated by a lack of pore microstructural data, in particular for granular ice and across the seasonal cycle, throat size, tortuosity, connectivity, and other microstructural variables were derived from X-ray computed tomography for brine-filled pores in seasonal landfast ice off northern Alaska. Data were obtained for granular and columnar ice during the ice growth, transition, and melt season. While granular ice exhibits a more heterogeneous pore space than columnar ice, pore and throat size distributions are comparable. The greater tortuosity of pores in granular (1.2 < τg < 1.7) compared to columnar ice (1.0 < τc < 1.1) compounded with a less interconnected pore space translates into lower permeability for granular ice during the growth season for a given porosity. The microstructural data explain findings of granular ice hindering vertical oil-in-ice transport during ice growth and transition stage. With granular ice more frequent in the changing Arctic, data from studies such as this are needed to inform improved modeling of porosity-permeability relationships.