Remote sensing and computational technique based assessment of significant controlling factors of South Lhonak glacial lake, Sikkim Himalaya
Abstract
The huge volume of South Lhonak glacial lake water is dammed by the moraines of South Lhonak glacier of Sikkim Himalaya. This lake has expanded to the extent of 87.37% between the years 2000 and 2018 pointing to an approximate expansion rate of 3.39 Sq.km yr-1. Hence, a few significant criteria have been taken into account to investigate whether this lake may become prone to glacial lake outburst flood (GLOF). The changing rate of the glacial lake area and volume were computed using empirical relations, loss in snow cover area of South Lhonak glacier, distance of the lake from its outlet path, mapping of the debris-covered area, slope, width and local relief have been computed based on remote sensing techniques using LANDSAT 5 (Thematic Mapper), LANDSAT 7 (Enhanced Thematic Mapper) and LANDSAT 8 (Operational Land Imager) as well as ALOS-PALSAR 12.5 m DEM (Digital Elevation Model) data. Information regarding soil type, tectonics and lithological details of the host terrain were obtained from secondary sources. Multi-criteria based Analytic Hierarchy Process (AHP) was performed to assess the importance of the controlling factors regarding the stability of the glacial lake dam. Towards this, consistency ratio was derived and observed to be <0.1 which is as per the subjective judgement of the factors considered to measure how consistent the judgements were. Further derivations were made towards AHP based prediction of likely factors which may contribute to the potential of outburst of this glacial lake in future.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C51B1276H
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0776 Glaciology;
- CRYOSPHERE