Sensitivity of the light field under sea ice to spatially inhomogeneous optical properties and incident light assessed with three-dimensional Monte Carlo radiative transfer simulations

► Bounds on light spread from three-dimensional Monte Carlo simulations. ► Spread reduced by absorption and optical anisotropy. ► Constraints for one-dimensional modeling of transmittance. ► Negligible effect of cylinders and small surface obstructions on transmittance. ► Phase function uncritical for transmittance through thick sea ice.