[A-CC32] Glaciology

[ACC32-P04] Estimation of Past Glacier Volume in the Baspa Basin, Western Himalaya

*Nidhiya Jose¹, Anil V Kulkarni¹, Sajeev Krishnan², Satheesh SK¹ (1.Divecha Centre for Climate Change, Indian Institute of Science, 2.Centre for Earth Sciences, Indian Institute of Science)

Keywords:Baspa Basin, Himalayan glacier, Mass loss, Ice thickness, moraine mapping

Strategies for water security and adaptability depend on an understanding of the long-term availability of water resources under changing climatic conditions. Rising temperature and altered precipitation patterns are causing Himalayan glaciers to rapidly lose mass. Since the worldwide Last Glacier Maxima (LGM), which occurred between 18 and 24 ka, the extent of ice has varied greatly. Moraine studies provide a deeper comprehension of the paleo-extent and chronology of glaciers. An essential parameter for assessing historical records of climate change is the glacier paleo extent. In this work, we used various remote sensing methods and numerical modelling to estimate the volume and extent of glacier in the Baspa basin during the global LGM. After considering the topographic factors of the area and the glacial geomorphology, we chose 61 glaciers from the Baspa basin. High-resolution imagery from Google Earth, Landsat 8, Sentinel, and Cartosat satellites was utilized to accurately delineate glacier boundaries and moraines. The HIGTHIM model was used to assess the current spatial distribution of ice thickness and volume. Paleo glacier volume was estimated using remote sensing, numerical methods, and glacier geomorphological features. The volume-area scaling equation was used to determine the volume on smaller glaciers (area <1 km²). Our research indicates that the area of the chosen glaciers is 1105.5 km², and the area of the moraine is 49.3 ± 0.46 km². There has been about a 52% decrease in ice volume from LGM, with the estimated past ice volume at LGM being 18.71 km³ and the present value being 8.51 km³. Ground Penetrating Radar (GPR) measurements from the glaciers provide high-resolution subsurface data on ice thickness, validating remote sensing estimates and improving our understanding of glacier dynamics and stability under climate change conditions. The study proposes estimating the mass loss in the current decades, which will help understand the acceleration of mass loss under global warming conditions.