Raphaël Larouche, Bastian Raulier, Christian Katlein, Simon Lambert-Girard, Simon Thibault, Marcel Babin

A better understanding of the radiative transfer of solar visible light within sea ice is crucial to study the Arctic energy balance and marine ecosystems. In this work, we showcase the utilization of a compact, consumer-grade 360-degree camera for measuring the in-ice spectral angular radiance distribution. This novel technique allows for the instantaneous acquisition of all radiometric quantities at a given depth with a compact, non-intrusive probe. This gives the opportunity to monitor the light field structure (mean cosines) from the atmosphere to the underlying ocean beneath ice. In this study, we report vertical profiles of the light field geometric distribution measured at two sites representative of distinct ice types: High Arctic multi-year ice and Chaleur Bay (Quebec) land fast first-year ice. We show that it is possible to empirically retrieve the depth-resolved internal optical properties by matching simulated profiles of spectral irradiances calculated with the HydroLight radiative transfer model to the observed profiles. As reported in other studies, the inverted reduced scattering coefficients were high (25.5 m-1, 37.5 m-1) in the first 20 centimeters for both sites (High Arctic, Chaleur Bay) and lower in the interior part of the ice (0.8 to 4.8 m-1, 2.8 to 7.2 m-1). Finally, due to the underdetermined nature of the inversion problem, we emphasize the importance of using the similarity parameter that considers the absorption and reduced scattering coefficients.