Tracer-based estimation of temporal variation of water sources: an insight from supra- and subglacial environments |
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Authors: | Naveen Kumar Tirumalesh Keesari S Chidambaram Shyam Ranjan Mohd Soheb |
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Institution: | 1. School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India;2. Isotopic and Radiation Application Division, Bhabha Atomic Research Centre, Mumbai, India;3. Water Research Institute, Kuwait Institute for Scientific Research, Safat, Kuwait |
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Abstract: | ABSTRACTThe temporal variations in electrical conductivity and the stable isotopes of water, δD and δ18O, were examined at Chhota Shigri Glacier, India, to understand water sources and flow paths to discharge. Discharge is highly influenced by supraglacially derived meltwater during peak ablation, and subglacial meltwaters are more prominent at the end of the melt season. The slope of the best fit linear regression line for δD versus δ18O, for both supraglacial and runoff water, is lower than that for precipitation (snow and rain) and surface ice, indicating strong isotopic fractionation associated with the melting processes. The slope of the local meteoric water line (LMWL) is close to that of the global meteoric water line (GMWL), reflecting that the moisture source is predominantly oceanic. The d-excess variation in rainwater confirms that the southwest monsoon is the main contributor during summer while the remainder including winter is mostly influenced by westerlies. |
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Keywords: | isotopic fractionation supraglacial subglacial d-excess Chhota Shigri Glacier India |
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