The Percolation Phase Transition in Sea Ice

TLDR

Sea ice undergoes a fluid‑transport transition at a critical brine volume fraction of ~5 % (≈ –5 °C for 5 ‰ salinity), above which brine can move through the ice and below which it becomes impermeable, a change that influences geophysical, biological, and remote‑sensing observations. Percolation theory is applied to explain this critical transport behavior in sea ice. By treating sea‑ice microstructure as a compressed powder, the authors theoretically predict the percolation threshold at about 5 % brine volume.

Abstract

Sea ice exhibits a marked transition in its fluid transport properties at a critical brine volume fraction pc of about 5 percent, or temperature Tc of about -5 degreesC for salinity of 5 parts per thousand. For temperatures warmer than Tc, brine carrying heat and nutrients can move through the ice, whereas for colder temperatures the ice is impermeable. This transition plays a key role in the geophysics, biology, and remote sensing of sea ice. Percolation theory can be used to understand this critical behavior of transport in sea ice. The similarity of sea ice microstructure to compressed powders is used to theoretically predict pc of about 5 percent.