Glacier Change Studies under Changing Climate Using Geospatial Tools and Techniques

The spatiotemporal study of the glaciers under the changing environment is critical from the freshwater availability, especially in the perennial rivers flowing out of them during the lean season. The Mrigthuni Glacier, one of the major glaciers in the Pindar River basin in Uttarakhand, has been selected as a study glacier for the present analysis. The long-term (1951-2018) meteorological data analysis indicated that the temperature increased in both the maximum ablation and accumulation period; however, the precipitation decreased during the primary accumulation period. The change detected in climate patterns provided an impetus to study its impact on the glacier using geospatial techniques. It was found that the glacier front retreated by 831.4 +/- 42 m at the rate of 32.94 m yr(-1) from 1990 to 2015. Further, the glacier accumulation area ratio has reduced from 55.63 to 53.22%, with a 66 m upward shift in equilibrium line altitude (ELA). The glacier's mass balance has reduced from 0.23 to 0.28 +/- 0.035 m w.e. during the analysis period, based on a general equation developed for northwestern Himalaya using the optical remote sensing data. Due to the limitations of optical data, Synthetic Aperture Radar (SAR) data was used to map glacier radar zones. The distinct percolation/refreeze, transient firn, and ablation zones were identified on the SAR data composite of the different seasons. Considering SAR-based ELA as the most accurate, the analysis confirmed the negative mass balance with a value of 0.62 +/- 0.036 m w.e. Therefore, it was concluded that SAR-based analysis might be vital for accurate glacier dynamics studies especially the mass balance.