Going with the Floes - Part 1

Sea ice is one of the least understood components of our climate.
Naturally its abundance or scarcity is a telling sign of climate
change, but sea ice is also an important actor in change as well,
insulating the ocean and reflecting sunlight. A branch of
mathematics called percolation theory helps explain how salt water
travels through sea ice, a process that is crucial both to the
amount of sea ice present and to the microscopic communities that
sustain polar ecosystems. By taking samples, doing on-site
experiments, and then incorporating the data into models of porous
materials, mathematicians are working to understand sea ice and
help refine climate predictions. Using probability, numerical
analysis, and partial differential equations, researchers have
recently shown that the permeability of sea ice is similar to that
of some sedimentary rocks in the earth.s crust, even though the
substances are otherwise dissimilar. One major difference between
the two is the drastic changes in permeability of sea ice, from
total blockage to clear passage, that occur over a range of just a
few degrees. This difference can have a major effect on
measurements by satellite, which provide information on the extent
and thickness of sea ice. Results about sea ice will not only make
satellite measurements more reliable, but they can also be applied
to descriptions of lung and bone porosity, and to understanding ice
on other planets. Image: Pancake ice in Antarctica, courtesy of Ken
Golden. For More Information: "Thermal evolution of permeability
and microstructure in sea ice," K. M. Golden, et al., Geophysical
Research Letters, August 28, 2007.