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Vertical resolution at 16 MHz was estimated approximately 2.5 m using pulse width of signal and velocity of EM waves in glacier ice. This study presents the application of GPR for ice thickness estimation and identification of subsurface features of glaciers in Himalayan region; however, one has to take care various crucial parameters required for GPR survey especially in Himalayan region. 8.6. Conclusions GPR is non-destructive technique which showed potential to ice thickness and englacial subsurface features in Chota Shigri glacier. A low frequency antenna (16 MHz) was used in the present study and survey have shown that the glacier thickness changed from 110 m to 150 m across the 400 m profile length as we move towards equilibrium line. Area-depth relationship has shown thickness of glacier ice approximately 101 m averaged over total glacier using Chaohai and Sharma (1988). The presence of point reflector (hyperbola signature) and non-bed reflector (due to englacial heterogeneities) could be helpful to understand the subsurface glacier phenomenon. GPR survey using MLF antenna was also carried out over ablation zone of Machoi glacier in Dras sector, J&K. This study demonstrates and provides an opportunity to develop area-depth relationship for Himalayan region in conjunction with remote sensing based information.
229 Monitoring Snow and Glaciers of Himalayan RegionSpace Applications Centre ISRO, Ahmedabad9. Use of Hyperspectral Data for Snowpack Characterization 9.1. Objective To explore and demonstrate the potential of hyperspectral data for snow pack characterization. 9.2. Scientific Rationale Hyperspectral imaging is simultaneous acquisition of images in many (usually 100 or more) narrow contiguous spectral bands e.g. Hyperion collects data in 220 channels in spectral range of 400-2500 nm at 10 nm interval or ASD field based spectrometer covers spectral range from 350-2500 nm with 3 nm spectral resolution in VIR and 10 nm spectral resolution in SWIR. Such datasets are extremely useful to develop new algorithms for retrieving various snow and glacier parameters. Initially, the snow cover mapping process was largely based on the conventional techniques such as manual delineation of snow cover boundaries, segmentation of ratio images and hard or crisp classification. Other analysis techniques such as visual, hybrid (visual and supervised classification) have also been used to estimate the areal extent of snow cover (Kulkarni et al., 2004; Kulkarni et al., 2006b). However, a major difficulty in snow cover monitoring using above techniques is mountain shadow and confusing signature of snow and cloud in the visible and near-infrared region. Because of the above-mentioned reasons, reflectance ratio/index approaches were introduced as they can remove the effects of some sensor radiometric errors and random changes in scene irradiance due to changing effects in the atmosphere and topographical changes across the scene (Dozier, 1989). The spectral region between 350 and 2500 nm is called the reflective part of the spectrum. In the Visible and Near-Infra Red (VNIR) region, the bulk optical properties of ice and water are very similar.