A larger volume of younger ice meant that a larger portion of it made it through the summer and was available to form second-year ice
Therefore, the proportions of ice types were grouped into three classes: thin ice (consisting of new ice, grey ice and grey-white ice), first-year ice (first-year ice, thin first-year ice, medium first-year ice, thick first-year ice), and thick ice (old ice, second-year ice
and multiyear ice).
The survey's route was designed so that the team would haul their sledges from the edge of the permanent sea ice of the Beaufort Sea, beginning on multi-year ice, transit briefly through a region primarily covered with first-year ice, then enter a region in which second-year ice
But, most of the 2009 September Arctic sea ice is thin first- or second-year ice
, rather than thicker, multi-year ice that used to dominate the region," said Meier.