A review of snow and ice albedo and the development of a newphysically based broadband albedo parameterization

摘要

We present a computationally simple, theoretically based parameterization for thebroadband albedo of snow and ice that can accurately reproduce the theoretical broadbandalbedo under a wide range of snow, ice, and atmospheric conditions. Depending on itsapplication, this parameterization requires between one and five input parameters. Theseparameters are specific surface area of snow/ice, concentration of light-absorbing carbon,solar zenith angle, cloud optical thickness, and snow depth. The parameterization isderived by fitting equations to albedo estimates generated with a 16-stream plane-parallel,discrete ordinates radiative transfer model of snow and ice that is coupled to a similarmodel of the atmosphere. Output from this model is also used to establish the physicaldeterminants of the spectral albedo of snow and ice and evaluate the characteristics ofspectral irradiance over snow-covered surfaces. Broadband albedo estimates determinedfrom the radiative transfer model are compared with results from a selection of previouslyproposed parameterizations. Compared to these parameterizations, the newly proposedparameterization produces accurate results for a much wider range of snow, ice, andatmospheric conditions.