WINTER SNOW COVER ON SEA-ICE IN THE WEDDELL SEA

Measurements of snow thickness, temperature, salinity, density, and st ratigraphy acquired during the 1992 Winter Weddell Gyre Study are pres ented. Results indicate that the winter snow cover on sea ice in the W eddell Sea is extremely variable. Extreme fluctuations in Antarctic sy noptic conditions (air temperature, precipitation; humidity, and wind speed) occur during the austral winter. They result in unique modifica tions and additions to the snow layer during the aging process and act to stabilize an otherwise easily wind-redistributed shallow snow cove r and develop well-packed drift features. The latter occur even over r elatively undeformed areas of sea ice and have a significant localized effect on the snow thickness distribution. Significant variability in snow grain size (mean 2.73 +/- 3.12 mm) and density (0.32 +/- 0.09 g cm(-3)) is observed as a result of cyclical switches between high- and low-temperature gradient metamorphism. Multiple icy layers indicate m ultiple thaw-freeze events. One such event occurred during a 3-day sta tion, during which the air temperature rose by 22 degrees C in 12 hour s (to approximately 0 degrees C). This paper also examines mechanisms for flooding of the snow-ice interface, including snow loading. Even w here the latter is not a factor, the layer of snow immediately above t he snow-ice interface is commonly damp and saline (>10 parts per thous and). Limitations in the data set are discussed, and comparisons are d rawn with other experiments.