Properties of snow overlying the sea ice off East Antarctica in late winter, 2007

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Toyota, Takenobu, Massom, Robert, Tateyama, Kazutaka, Tamura, Takeshi, Fraser, Alexander
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier
• Subjects: Antarctic snow on sea ice; Thermal conductivity of snow; Flooding; Snow ice formation; Air-ice drag coefficient; Retrieval of ice thickness from satellite; 452; Antarctic; East Antarctica; Wilkes Land; Antarc*; Antarctica; Sea ice
• Online Access: http://hdl.handle.net/2115/46198; https://doi.org/10.1016/j.dsr2.2010.12.002

The properties of snow on East Antarctic sea ice off Wilkes Land were examined during the Sea Ice Physics and Ecosystem Experiment (SIPEX) in late winter of 2007, focusing on the interaction with sea ice. This observation includes 11 transect lines for the measurement of ice thickness, freeboard, and snow depth, 50 snow pits on 13 ice floes, and diurnal variation of surface heat flux on three ice floes. The detailed profiling of topography along the transects and the d18O, salinity, and density datasets of snow made it possible to examine the snow-sea-ice interaction quantitatively for the first time in this area. In general, the snow displayed significant heterogeneity in types, thickness (mean: 0.14 ± 0.13 m), and density (325 ± 38 kg m^[-3]), as reported in other East Antarctic regions. High salinity was confined to the lowest 0.1 m. Salinity and d18O data within this layer revealed that saline water originated from the surface brine of sea ice in 20% of the total sites and from seawater in 80%. From the vertical profiles of snow density, bulk thermal conductivity of snow was estimated as 0.15W K^[-1] m^[-1] on average, only half of the value used for numerical sea ice models. Although the upward heat flux within snow estimated with this value was significantly lower than that within ice, it turned out that a higher value of thermal conductivity (0.3 to 0.4 W K^[-1] m^[-1]) is preferable for estimating ice growth amount in current numerical models. Diurnal measurements showed that upward conductive heat flux within the snow and net long-wave radiation at the surface seem to play important roles in the formation of snow ice from slush. The detailed surface topography allowed us to compare the air-ice drag coefficients of ice and snow surfaces under neutral conditions, and to examine the possibility of the retrieval of ice thickness distribution from satellite remote sensing. It was found that overall snow cover works to enhance the surface roughness of sea ice rather than moderate it, and increases the drag ...