Assessing the Variation of Glaciers Velocity in Hunza Basin, Gilgit Baltistan Using Advanced Geospatial Techniques.

World's largest glaciers lie in Hindu Kush Himalayan (HKH) outside polar region, are the source of fresh water which accommodates the needs of millions of people living downstream. Impact of changing climate on cryosphere can be measured critically from glacier movement due to global warming. Due to complex terrain and unpredictable weather, it is not feasible to measure glaciers' velocity and movement through field surveys physically. For this purpose, the current study aimed to assess the variation of glaciers velocity using advance geospatial technique like the co-registration and correlation (COSI-CORR) of optically sensed satellite images. Time-series analysis on the Landsat-8 data (2013-2020) revealed successfully for computing the surface ice velocity of glaciers of Hunza Basin. Results show that the velocity of a glacier increases with the altitude whereas speed decreases at the terminus. Moreover, it has been noted from spatial patterns of glacier surface ice velocity that the tributary glaciers contribute to the mainstream glacier velocity significantly, which increases at the terminus. Subsequently, the varying ice velocity was determined by orientation, debris cover, glacier size, and altitude for glaciers. The study recommended to regularly monitor the dynamics of glaciers in this region to cater the impacts of global warming and climate change. [ABSTRACT FROM AUTHOR]