Brief communication: Conventional assumptions involving the speed of radar waves in snow introduce systematic underestimates to sea ice thickness and seasonal growth rate estimates

• Published in: The Cryosphere
• Main Authors: Mallett, Robbie D. C., Lawrence, Isobel R., Stroeve, Julienne C., Landy, Jack C., Tsamados, Michel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: article; Verlagsveröffentlichung; Arctic; Sea ice; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-14-251-2020; https://noa.gwlb.de/receive/cop_mods_00050398; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050009/tc-14-251-2020.pdf; https://tc.copernicus.org/articles/14/251/2020/tc-14-251-2020.pdf

Pan-Arctic sea ice thickness has been monitored over recent decades by satellite radar altimeters such as CryoSat-2, which emits Ku-band radar waves that are assumed in publicly available sea ice thickness products to penetrate overlying snow and scatter from the ice–snow interface. Here we examine two expressions for the time delay caused by slower radar wave propagation through the snow layer and related assumptions concerning the time evolution of overlying snow density. Two conventional treatments introduce systematic underestimates of up to 15 cm into ice thickness estimates and up to 10 cm into thermodynamic growth rate estimates over multi-year ice in winter. Correcting these biases would impact a wide variety of model projections, calibrations, validations and reanalyses.