Detection of Glacier Lakes Buried under Snow by RISAT-1 SAR in the Himalayan Terrain

Synthetic aperture radar (SAR) signals penetrate through the dry snow and cloud providing crucial data over the Himalayan temperate glaciers and complement the optical images. In the present study, RISAT-1 C band and AWiFS images of winter/ablation period over Samudra Tapu and Gepang Gath moraine dammed lakes (MDLs) in Himachal Pradesh have been analysed. Backscattering coefficient of the lake was observed to be low throughout the year. Penetration depth of SAR into dry snowpack was calculated to vary from 4 to 22 m for a range of snow density (0.1-0.5 g/cm³), whereas it was estimated to be 1.20- 2.01 m based on ground observations for 30 January and 24 February 2013. The present study provides results of RISAT-1 C-band penetration up to ~2 m through the snowpack to detect MDLs in the Himalayan terrain. The detection of MDLs using the backscattering images of winter season was validated with synchronous AWiFS sensor images.