Radars can ‘see through the clouds’ and active radars offer unprecedented horizontal spatial resolution – but what do they actually ‘see’? How can we measure snow depth on ground in a way that will facilitate the progress in the satellite altimetry retrievals of sea ice thickness? Sea ice and snow surface has typically large horizontal spatial variability already at distances as short as a meter. When working with point data some surface types can hardly be sampled. Still, despite the huge cost of collecting distributed data, its representativity is often questioned and the work itself is always suffering by strict safety limitations. What is the best strategy for sea ice thickness and snow depth sampling to make it most useful for satellite remote sensing validation? Here we present what we learned at MOSAiC and what we are up to with the support of CIRFA…