The observed changes of Arctic sea ice during the last decades have a strong impact on interactions with the atmosphere and ocean. Due to a more seasonal ice cover the transmitted and absorbed solar radiation (light) of Arctic sea ice increases significantly. This, in turn, affects sea ice melt as well as biological and geochemical processes in and under Arctic sea ice. Up to now, it is not possible to observe light transmission sufficiently well over large regions and during different seasons. Hence, to obtain Arctic-wide estimates of light under sea ice, it is necessary to develop new methods. Here we present an upscaling method based on parameterization of light transmittance and remote sensing and reanalysis data.