Deciphering the Properties of Different Arctic Ice Types During the Growth Phase of MOSAiC: Implications for Future Studies on Gas Pathways

The increased fraction of first year ice (FYI) at the expense old (second-year (SYI) and multi-year (MYI)) likely affects permeability Arctic cover. This in turn influences pathways gases circulating therein exchange interfaces with atmosphere ocean. We present sea temperature salinity time series from different types relevant to temporal development brine drainage efficiency freeze-up October onset spring warming May. Our study is based on a dataset collected during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) Expedition 2019 2020. These physical properties were used derive Rayleigh numbers. main sites included FYI SYI. latter was composed an upper layer residual that had desalinated but survived previous summer melt became Below this new first-year formed. As has no direct contact atmosphere, we call it insulated (IFYI). residual/SYI-layer also contained refrozen ponds some areas. During freezing season, consistently impermeable, acting as barrier gas between While both SYI temperatures responded similarly atmospheric events, more resilient volume changes because its low ( < 2). Furthermore, later bottom growth observed comparison FYI. projected increase permeable autumn coming decades may favor atmosphere-ice interface when acts source relative atmosphere. areal extent decreasing, so thickness freeze-up. sets foundation studies dynamics within column interfaces, i.e.