On the importance to consider the cloud dependence in parameterizing the albedo of snow on sea ice

• Main Authors: Foth, Lara, Dorn, Wolfgang, Rinke, Annette, Jäkel, Evelyn, Niehaus, Hannah
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2023
• Subjects: article; Verlagsveröffentlichung; Arctic; albedo; Sea ice
• Online Access: https://doi.org/10.5194/egusphere-2023-634; https://noa.gwlb.de/receive/cop_mods_00065830; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00064340/egusphere-2023-634.pdf; https://egusphere.copernicus.org/preprints/2023/egusphere-2023-634/egusphere-2023-634.pdf

The impact of a revised snow surface albedo parameterization, which explicitly considers the cloud dependence of the snow albedo, is evaluated in simulations of a coupled regional climate model of the Arctic. The revised snow surface albedo parameterization leads to a more realistic simulation of the variability of the surface albedo during the snow melt period in late May and June. In particular, the reproduction of lower albedo values under cloud-free/broken-cloud conditions during the snow melt period represents a major improvement and results in an earlier disappearance of the snow cover and an earlier onset of sea-ice melt. In this way, the consideration of the cloud dependence of the snow albedo results in an amplification of the two-stage snow-albedo/ice-albedo feedback in the model. This finds expression in additional loss of sea-ice volume of more than 1000 km3 and additional reduction of summer sea-ice extent of around 250,000 km2 during one melting period, with accumulating magnitude of the overall changes in subsequent years.