Modeled Effects of Encapsulated Crude Oil on Light Transmission Through Sea Ice

As part of ongoing research to further advance a range of oil spill response technologies in the Arctic, nine oil and gas companies established the Arctic Oil Spill Response Technology Joint Industry Programme (JIP) in 2012. One research theme is designed to expand the industry's remote-sensing and monitoring capabilities. A suite of sensors was tested on a saltwater ice sheet grown in the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL) Ice Engineering Research Facility test basin while oil was injected under the ice at different points in the ice growth. The ice continued to grow after the oil injection, allowing the oil to become encapsulated so testing could occur with various thicknesses of ice below the oil. Measurements of apparent optical properties were taken before and after the injection of oil and during various stages of ice growth. We have used a Monte Carlo model of radiative transfer for sea ice [Light et al., 2003] to explore light transmission through sea ice containing encapsulated oil. This model uses a cylindrical domain, making it well-suited for determining how large a pool of oil encapsulated in a given thickness of ice must be before it is detectable from beneath the ice cover. We use this model in combination with the optical observations to predict the amount of light transmitted and reflected from sea ice of various thicknesses containing oil. We also examine the effects of a scattering layer on the ice surface, as would commonly be present in the Arctic, either in the form of snow or the surface scattering layer that develops on melting ice. We evaluate the feasibility of distinguishing between different types of oil based on the spectral signature of light transmitted through the ice. Further model sensitivity studies yield insight about the effects of the distribution of the oil within the ice cover. Light, B., G. A. Maykut, and T. C. Grenfell (2003), A two-dimensional Monte Carlo model of radiative transfer in sea ice, J. Geophys. Res., 108(C7), 1-18, doi:10.1029/2002JC001513.