Snow extent mapping in Alpine areas using polarimetric SAR data.
Résumé
This paper proposes one original technique to map the snow extent in the French Alps from SAR measurements using SIR-C fully polarimetric winter/summer data sets at L and C-bands. The method relies on a multi-frequency two-step approach. Basic natural media types, like surface and forest, are first discriminated over the scene under observation from a polarimetric analysis of summer measurements at L-band. Secondly, the presence of snow is then detected separately over each media type using the H-A-a polarimetric decomposition theorem. An original PCVE (polarimetric contrast variation enhancement) procedure provides optimal emission/reception polarisation states that maximise the C-band winter to summer response of snow-covered areas. The results are compared to Landsat optical images acquired simultaneously.