University of Twente Student Theses


Glacier facies classification and comparison of velocity estimation techniques using sar and optical datasets

Manimaran, Aravind (2023) Glacier facies classification and comparison of velocity estimation techniques using sar and optical datasets.

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Abstract:Glaciers are important features of the cryosphere that command the microclimate and water availability that are relied upon by many communities. The phenomenon of global warming has put the fragile glacial ecosystem of the Himalayas at the risk of recession. This detrimental effect is caused by variations in multiple parameters of the glacier. It affects the millions who reside downstream that rely on the water source fed by the glaciers. Bada Shigri, Chota Shigri and Gepang Gath of the Chandra basin, are such glaciers that directly contribute to the water level of the Chandra River. Hence, this study focusses on classifying the various zones of the glaciers with SAR imagery to map the accumulation zone, ablation zone and the resulting equilibrium altitude line (ELA).. The glaciers were classified by using satellite imagery from three different seasons- early summer, late summer, and winter. Five zones namely upper percolation zone, middle percolation zone, lower percolation zone, bare ice and debris were mapped and quantified with a random forest classifier with an out of bag accuracy of 97%. All three glaciers showed an increase in elevation of the ELA depicting an increase in area of ablation zone through the years of 2019-2022. The study also estimates the velocity of each glacier, an important parameter that keeps a check on glacier’s health and hazards, using feature tracking, Time series InSAR (Using MintPy) methods on SAR and optical imageries. The velocity showed a downward trend through 2019-2022. The obtained values were compared with historical dataset and GoLive global velocity dataset. Although the results aligned with the historical velocity trend, it showed a high deflection from the values obtained from GoLive
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Subject:38 earth sciences, 43 environmental science
Programme:Geoinformation Science and Earth Observation MSc (75014)
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