Simulated Ka- and Ku-band radar altimeter height and freeboard estimation on snow-covered Arctic sea ice

Abstract. Owing to differing and complex snow geophysical properties, radar waves of different wavelengths undergo variable penetration through snow-covered sea ice. However, the mechanisms influencing altimeter backscatter from ice, especially at Ka- Ku-band frequencies, impact on scattering horizon or “track point” (i.e. layer depth detected by re-tracker) are not well understood. In this study, we evaluate with respect ice floe buoyancy using a first-order model Archimedes principle. The is forced data European Space Agency (ESA) climate change initiative (CCI) round-robin package, in which NASA's Operation IceBridge (OIB) climatology included, detailed property profiles Canadian Arctic. Our simulations demonstrate that track point difference function depth; however, simulated much smaller than what reported literature CryoSat-2 Ka-band SARAL/AltiKa satellite observations. We argue discrepancy differences sensitive type its associated properties. Snow salinity first increasing when thin then decreasing thick (>0.1 m). A relationship between found. This has implications for (1) use conversion freeboard into thickness (2) variability measured derived thickness. For both (2), versus actual relatively small freeboard, only raising 0.03 times climatological plus real depth. buoyancy. study serves enhance our understanding microwave interactions towards improved accuracy retrievals via combination currently operational ESA's forthcoming dual-frequency CRISTAL missions.