Mathematician on Ice

Abstract

A winter expedition into frigid Antarctic waters no pleasure cruise. Screaming winds, bone-chilling temperatures, high seas, driving snow, and crunching ice create conditions that try the hardiest of souls. It's an unlikely place to find a mathematician. Last year's 8-week voyage of the icebreaking research vessel Aurora Australis from Tasmania wasn't Kenneth M. Golden's first venture into the Antarctic ice pack. An applied mathematician at the University of Utah in Salt Lake City, he had also studied sea ice on three previous Antarctic outings. Foul weather never kept Golden from relishing an Antarctic voyage. I loved watching the waves, he says. When the sun squeaked through storm clouds during the few hours of daylight, he could also enjoy spectacular views of giant icebergs, crumpled ice sheets, and penguins waddling across snow or skimming the water. About four dozen researchers were aboard the icebreaker on its 1999 voyage. Their destination was a sizable region, called a polynya, of open water and thin ice that had appeared in the ice-bound waters near the toe of the Mertz Glacier off the Antarctic coast. The sea-ice pack insulates the ocean from the atmosphere. A hole in this lid permits a significant amount of heat to escape from the water to the much chillier air. At the same time, surface waters cool, become denser, and sink, contributing to ocean circulation (SN: 7/15/00, p. 42). New ice begins to form, filling in the hole. As the boundary layer between ocean and atmosphere in polar regions, sea ice has a significant impact on global climate, Golden notes. Polynyas play a crucial role in energy exchange and ice formation, so the occurrence of one inevitably draws the attention of researchers. On a broader front, sea ice is most important in the context of climate variability and both as an indicator and an agent of climate change, says geophysicist Hajo Eicken of the University of Alaska in Fairbanks. The need to understand better the physical properties of sea ice, track its movements, and remotely monitor its thickness, temperature, and roughness has prompted a number of recent studies of its structure. In May at a Society for Industrial and Applied Mathematics meeting in Philadelphia on mathematical aspects of materials science, Golden described how new mathematical models have provided insights into the way brine seeps through ice, carrying heat and nutrients. A vast expanse of sea ice off Antarctica's coast.