Seasonal contrasts in snow-cover characteristics on Ross Sea ice floes

Snow-cover characteristics on ice floes in the Ross Sea, Antarctica, were examined during cruises in autumn 1998 and summer 1999. The autumn snow cover was shallower, colder and had higher and more variable salinity, and smaller single and composite grain-sizes than the summer snow cover. The autumn snow cover was dominated by rounded particles in chains of grains and clusters, while the summer snow cover was composed primarily of melt clusters. There was extensive flooding of the summer snow cover at the snow/ice interface. The summer snow cover was nearly isothermal and close to the melting point. It exhibited obvious signs of melting and refreezing in the form of ice lenses, pipes and superimposed ice, although no melt ponds were evident. Many of the ice tenses were located directly above the saline standing water found on most of the summer ice floes.