Passive microwave retrieval of snow depth remains constrained by snow and ice conditions. By combining the Snow Microwave Radiative Transfer model with global sensitivity analysis, this study quantifies how snow grain radius, density, and sea ice type affect snow depth retrievability across channels. The small grain radius of new snow limits retrieval performance and increases its sensitivity to sea ice type, while the use of the 89 GHz channel may help address this limitation.

Arctic sea ice thickness is commonly estimated using radar measurements from satellites. This technique assumes that the snow on sea ice is "invisible" to the radar signals. We studied if this assumption is valid and found that the radar measurements work well in cold conditions, when air temperatures are below –10 °C. However, the radar measurements can overestimate ice thickness during warmer periods, especially if there is new snowfall and if the snow contains salt.