DETERMINATION OF THE DEPTH-DEPENDENT SCATTERING COEFFICIENT IN SEA-ICE

Measurements of the spatial spreading of light in typical first-year s ea ice in McMurdo Sound, Antarctica, have been characterized in terms of depth dependent scattering using Monte Carlo simulations. The resul ts are shown to place constraints on models of the optical transmissio n of sea ice and on the relationship of the optical scattering paramet ers to the physical structure of the ice. Comparisons for different si tes and seasons within a given year and between years are presented. T he backscattering spatial profiles are shown to fix the scattering par ameters of the strongly scattering top layer and the horizontal compon ent of the anisotropic scattering parameter in the bulk layer. The tra nsmission spatial profiles determine the anisotropy of the bulk layer and the absorption by algae near the base of the ice. It is demonstrat ed that the top layer is very sensitive to warming of the ice and that the scattering properties of this layer largely determine the albedo of sea ice while the transmission is affected by the nature of the top layer, the scattering in the bulk layer, and the absorption in the al gal layer. A quantitative relationship between the scattering length a nd the air volume fraction is demonstrated.