K. Golden
University of Utah
Homogenization Problems for Sea Ice
Sea ice is a composite of pure ice with brine and air
inclusions on the submillimeter scale. Typically one is interested in the
effective physical properties of sea ice, such as fluid permeability,
electrical permittivity and conductivity, and mechanical properties,
over much larger length scales. Thus it is natural to apply techniques
of homogenization to the analysis of sea ice material properties.
Sea ice is distinguished from many other porous media, such as
sandstones or bone, in that its microstructure and bulk properties
depend strongly on temperature. Above a critical value of around
-5 degrees C, sea ice is permeable, allowing transport of brine,
nutrients, biomass, and heat through the ice. In the Antarctic, these
processes play an important role in air-sea-ice interactions, in the
life cycles of sea ice algae, and in remote sensing of the pack.
Recently we have used percolation theory to model the transition in the
transport properties of sea ice. The results are based on the close
similarity of sea ice microsrtucture to that of compressed polymeric
powders. We give an overview of these results, and how they explain
data we took in Antarctica. We also describe recent work in applying
homogenization to analyze the effective electromagnetic properties
of sea ice, and in developing a theory of inverse homogenization
for recovering information about the microstructure from bulk
electromagnetic measurements.
