Arctic Sea Ice Microstructure Observations Relevant to Microwave Scattering
DOI:
https://doi.org/10.14430/arctic1297Keywords:
Bubbling, Cores, Hummocks, Ocean-atmosphere interaction, Physical properties, Puddles, Remote sensing, Sea ice, SAR, SIMMS, Resolute Bay, NunavutAbstract
Sea ice microstructure characteristics relevant to ice microwave scattering were studied during SIMMS'91 field experiment in Resolute Bay in May/June 1991. Thin sections of the top 300 mm layer of first-year ice (from hummocks and melt ponds) were prepared and examined. Analysis is based mostly on qualitative observations, although statistics on bubble dimensions and geometry were obtained from digital analysis of thin section photographs. First-year ice featured mostly an oriented columnar grain structure. Both spherical and needle-shaped brine pockets were observed. In multi-year ice, a variety of grain structures and inclusion patterns were observed from the same floe. Hummock and melt pond ice are different in terms of grain structure and air bubble contents. Air bubbles in hummock ice are highly random and interconnected, especially near the surface. At lower depths, they retain simpler shapes and become oriented parallel to the dominant grain growth direction. In melt pond ice, two types of air inclusions whose typical dimensions differ by an order of magnitude were observed. Significant spatial variability of multi-year microstructure within a single floe is demonstrated.
Key words: sea ice, ice microstructure, ice microwave scattering, SAR ice signatures, air bubbles in sea ice
