A comparison of physical properties and strength of decaying first-year ice in the Arctic and sub-Arctic

Abstract

Measurements made on first-year ice in the Arctic and sub-Arctic are used to show that ice from both regions decays in a similar manner during the spring/summer melt season. One notable difference is that melt-induced changes in sub-Arctic Labrador occur about 2 months earlier than in the Arctic. In both regions, the temperature and strength of the ice change gradually over the season, whereas the bulk salinity and thickness of the ice do not change substantially until later in the season, when the ice becomes isothermal at a temperature of -1.8°C. Results show that the seasonal decrease in the strength of first-year sea ice and the temperature-induced increase in brine volume are correlated. Once the ice is devoid of salt in late summer, the air volume continues to increase but has minimal effect on the ice strength.