Data assimilation of multilayer snowpack on Argentière glacier, using X-band SAR data, DMRT and a detailed snowpack model

This study discuss the potential of using remote sensing data from Synthetic Aperture Radar (SAR), couple with Dense Media Radiative Transfer (DMRT) model, to constrain the snowpack's optical grain size and density calculated by the detailed snowpack model Crocus. A snowpack Electromagnetic Backscattering Model (EBM) based on DMRT compatible with X-band and Ku-band frequencies is developed from the previous one by Longépé et al., 2009. From measured or simulated snowpack stratigraphic profiles consisting of snow optical grain size, density, the model calculates the backscattering coefficient σ 0 for co-polarized channels (HH and VV). Next, from the EBM, the adjoint operator is developed and used in a variational assimilation scheme in order to minimize the discrepancies between simulations and SAR image data observations. A time series of TerraSAR-X acquisitions on Argentière glacier (Chamonix Mont Blanc, France) is used to test the proposed scheme.