Austral Summer Sea Ice Melt Revealed in Antarctic ERS-1/2 and NSCAT Scatterometer Data

Introduction The first in-situ field observations of Antarctic austral summer sea-ice melt were made in the Bellingshausen Sea by Arctowski (1908) on Belgica in 1899, and later by Wordie (1921) during the ill-fated drift of Endurance in the Weddell Sea from 1914-1916. It has been 100 years since these pioneering ship drift experiments, yet little more is known about the spatial extent, duration, frequency of seasonal surface melting of sea ice during the austral summer (December through March), or indeed its interannual variability. Both experimenters independently reported that Antarctic sea ice does not experience widespread vigorous summer surface melting, as is characterized by the formation of extensive ponding at melt maximum in the Arctic (Gogineni et al., 1992). Despite surrounded by relatively warm ocean surface waters, some energy balance studies have suggested that the resulting combined surface radiative and turbulent heat fluxes are insufficient to induce widespread, protracted surface melting (Andreas and Ackley, 1982). The appearance of surface melting on sea ice is particularly important since it modifies the albedo of the surface of the ice and thus has significant impact on the radiative component of the surface energy balance during summer.