Growth, structure, and properties of sea ice.

Polynyas and leads are openings in pack ice due to divergences in ice drift and to local melting. They are the vents and windows to the polar oceans. In winter they are a major source of brine during freezing and a locus for gas exchange. Large sensible heat fluxes, together with evaporation and longwave radiation from a very small percentage of open water and thin ice, dominate regional heat budgets. In summer, solar radiation is absorbed by open water but is reflected from snow-covered pack ice. Experiments and models describing these processes are reviewed.

Polynyas and leads: An overview of physical processes and environment

On the geophysical scale sea ice is a thin, fragile, dynamic, solid layer that forms under the thermodynamic conditions that occur near the Poles. There it serves as a boundary between two much larger fluid bodies — the ocean and the atmosphere. Typical scales of interest would be 103 to 106 m. In the present paper we take a more detailed view, focusing on the ice itself at scales ranging between 100 and 10−3 m, with an occasional glimpse at a scale of 10−10 m. It is our purpose to help the reader understand the internal structure of sea ice, how this structure develops, and how it affects the bulk properties of the ice. Although this is a subject that has received little attention in comparison to similar studies of metals and ceramics, it is, in our view, very important, as many details in the behavior of sea ice are structurally controlled. The variations in structure are, in turn, determined by the environmental conditions under which the ice has formed.

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The Growth, Structure, and Properties of Sea Ice

Sediments in Arctic sea ice: Implications for entrainment, transport and release

Ice has a significant impact on the polar and sub-polar benthos, but relationships between corresponding physical and biological processes are not yet sufficiently understood. Sea ice contributes to a vertical zonation in shallow waters, which also experience other important disturbances. Due to the length of the non-glaciated coastline, sea ice is of greater relevance in the north than in the south. Scouring by icebergs and ridged sea ice causes an increased diversity when different recolonisation stages coexist. Frequently scoured areas do not recover, especially in the Antarctic, due to slow growth rates of the fauna. Iceberg grounding in the Arctic is mainly restricted to the western Eurasian and northeastern American shelf, including Greenland. Around Antarctica, scouring is more evenly distributed. Glacier termini prevent sessile animals from settling in their proximity where only few motile species occur.

S Martin

Papers

Frazil Ice in Rivers and Oceans