Optical beam-spread profiles were measured on sea ice from McMurdo Sound, with a view to understanding the role of microstructure in the scattering of light in sea ice. These experiments were performed on 1.79 m thick undeformed, first-year sea ice located offshore of Cape Evans during the Austral Summer, October 1998. These measurements are one part of data collected in the Ross Sea region, with ... collections also on first-year sea ice in the Ross Sea during the Austral Winter, May 1998, and late Austral Summer, January 1999 from the NBP 98-3 and NBP 99-1 cruises of the Nathaniel B Palmer.
The experiments themselves measured the visible beam-spread due to scattering from the air bubbles and brine inclusions contained within the sea ice, and were performed in situ. Two wavelengths were used to identify absorption due to algae trapped within the sea ice. Physical properties of the sea ice were obtained from concurrent K131 field work in McMurdo Sound, and from M.O. Jeffries and K. Morris for the NBP cruises. The beam-spread data were collected with the aim of performing Monte Carlo modelling of light transport within the ice. These models were successfully able to fit the data, providing simple empirical models of the sea ice optical properties.