Assessing the retrieval of cloud properties from radiation measurements over snow and ice

We critically review and improve a simple method to extract year-round records of cloud optical thickness from radiation measurements made by automatic weather stations (AWSs) over snow and ice surfaces. A ‘longwave-equivalent cloudiness’, Nε, obtained from longwave radiation measurements, is combined with the effective cloud optical thickness, τ, from shortwave data, to obtain consistent, year-round information on cloud properties. The method is applied to radiation data from six AWSs in Dronning Maud Land, Antarctica, and the ablation area of the West-Greenland ice sheet. The good correlation between daily-mean Nε and τ for all locations (0.77 <r