Scattering Mechanism Based Snow Cover Mapping Using RADARSAT-2 C-Band Polarimetric SAR Data

Monitoring of snow cover over large areal extent requires the use of remotely sensed satellite data. Conventional snow cover mapping algorithms using SAR data have seldom utilized target scattering information for land cover characterization. In this paper, an approach is proposed for snow cover mapping that utilizes the Touzi eigenvalue-eigenvector-based decomposition parameters viz., the scattering helicities (tau(m); m = 1, 2), the scattering magnitude (alpha(s)), and the entropy (H). The seasonal variation of these parameters is used as an indicator of scattering mechanism dominance in the proposed algorithm. The C-band RADARSAT-2 (FQ20) winter-summer image pairs over the Manali-Dhundi region of Himachal Pradesh, India, located in the western Hindu-Kush Himalayas are used in this paper. The proposed methodology is able to delineate the snow-covered areas suitably. The temporal extent of the cover is also quantified and validated with field campaigns and weather data. Furthermore, the results obtained from the proposed methodology are compared with NDSI-based snow cover maps derived from LANDSAT-8 images.