Stronger winds explain puzzling growth of sea ice in Antarctica

vinces99 writes: As NOAA announces a new record for the extent of sea ice in Antarctica, a new modeling study to be published in the Journal of Climate shows that stronger polar winds lead to an increase in Antarctic sea ice, even when Earth's overall climate is getting warmer. The study by Jinlun Zhang, a University of Washington oceanographer, shows that stronger westerly winds swirling around the South Pole can explain 80 percent of the increase in Antarctic sea ice volume during the past three decades. The polar vortex that swirls around the South Pole is not just stronger than it was when satellite records began in the 1970s, it also shoves the sea ice together to cause ridging. Stronger winds also drive ice faster, which leads to still more deformation and ridging. This creates thicker, longer-lasting ice, while exposing surrounding water and thin ice to the blistering cold winds that cause more ice growth. A computer simulation that includes detailed interactions between wind and sea shows that thick ice — more than 6 feet deep — increased by about 1 percent per year from 1979 to 2010, while the amount of thin ice stayed fairly constant. The end result is a thicker, slightly larger ice pack that lasts longer into the summer.