EGU General Assembly 2020
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the Creative Commons Attribution 4.0 License.

Linking glacial lake expansion with glacier dynamics: An assessment of the South Lhonak lake, Sikkim Himalaya

Saurabh Kaushik1,2, Pawan Kumar Joshi3,4, Tejpal Singh1,2, and Anshuman Bhardwaj5
Saurabh Kaushik et al.
  • 1CSIR-Central Scientific Instrument Organisation, Chandigarh 160030, India (
  • 2Academy of Scientific and Innovative Research (AcSIR-CSIO), CSIR-CSIO campus, Chandigarh 160030, India
  • 3School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
  • 4Special Centre for Disaster Research, Jawaharlal Nehru University, New Delhi 110 067, India
  • 5Division of Space Technology, Department of Computer Science, Electrical and Space Engineering, Luleå University of Technology, Luleå, Sweden

The Himalayan Cryosphere is imperative to the people of south and central Asia owing to its water availability, hydropower generation, environmental services, eco-tourism, and influences on overall economic development of the region. Additionally, this influences the energy balance of the earth and contributes significantly to the sea level rise. Therefore Himalayan Cryosphere remains center of attraction for scientific community.  Glacier dynamics, seasonal snow and glacial lakes are studied at various scales using a combination of remote sensing and field observations. The existing literature reveals heterogeneous behavior of Himalayan glaciers which is largely influenced by climate change, debris cover and presence of glacial lake at the terminus. There are very limited studies that attempt to comprehend glacier dynamics and lake expansion in the Eastern Himalayan region. Therefore the present study aims to demonstrate link between glacier dynamics and lake expansion of South Lhonak glacier which is situated in the northern Sikkim. Multitemporal remote sensing data (Landsat, 1979-2019) and climate data (1990-2017) observed at Gangtok meteorological station are used in the study. The results reveal that the lake has expanded with a rate of 0.026 km2 yr-1 during the last four decades. The preliminary results show strongly imbalanced state of glacier, as glacier has deglaciated (area and length), and surface flow velocity and ice thickness have reduced significantly. The statistical analysis (Mann Kendall and Sens slope) of climate data measured at Gangtok meteorological station shows an accelerated trend of mean maximum (0.031°C yr-1) and mean minimum (0.043°C yr-1) temperatures (95% confidence interval). Whereas, no significant trend in total annual precipitation was observed. Inference can be drawn from study that glacier slow down and retreat contribute significantly to the glacial lake expansion under the influence of climate change, such lake expansion pose anticipated risk of glacial lake outburst in the region.

How to cite: Kaushik, S., Joshi, P. K., Singh, T., and Bhardwaj, A.: Linking glacial lake expansion with glacier dynamics: An assessment of the South Lhonak lake, Sikkim Himalaya, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-685,, 2020.