Potential for estimation of snow depth on Arctic sea ice from CryoSat-2 and SARAL/AltiKa missions

•This study explores the potential of multi-satellite to study snow covered sea ice.•A comparison with in situ snow measurement is presented.•Spatial pattern and temporal evolution of snow depth are shown.•Changes in snow cover are examined.•Impacts on sea ice volume estimates are discussed.

The scattering properties of the radar signal at Ka and Ku-band frequencies are investigated using a theoretical model and snow grain observations obtained during previous field campaigns. Our results show that the combination of radar altimeters operating at these two frequencies should allow for the retrieval of snow depth over Arctic sea ice. We estimate uncertainties of the ice surface position in relation to crossover observations over sea ice and show that the accuracy of the crossover methodology with short time gap (3 days or less) is better than 3 cm. Comparison of the CryoSat-2/AltiKa retrieved snow depth with in situ measurements provided by Operation IceBridge shows a good agreement with a Root Mean Square Error (RMSE) of 5 cm. Analysis of the CryoSat-2/AltiKa retrieved snow depths over three winters (2013-2015) reveals a thinner snow cover on both Multi-Year (32%-57%) and First-Year Ice (63%-75%) relative to the 1954-91 Warren climatology, suggesting the need for more contemporary year-round and basin-scale snow depth fields.