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| Titel |
Seasonal variation of glacial melt proportion in the headwaters of the Ganges River: Preliminary results |
| VerfasserIn |
Indra Sen, Jordon Hemingway, Deep Sengupta, Rajiv Sinha, Bernhard Peucker-Ehrenbrink, Anirban Chakraborty |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250113811
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| Publikation (Nr.) |
 EGU/EGU2015-14042.pdf |
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| Zusammenfassung |
| The effect of global warming on Hindu Kush- Himalayan (HKH) glaciers is of global
concern as they are the source of many large rivers in the Indian subcontinent such as the
Indus, Ganges, and Brahmaputra. Questions and concerns have been raised about the melting
of the Himalayan glaciers, and how this will impact downstream water supplies, hydropower
generation, irrigation, and food security issues. Of all the HKH glaciers, the Gangotri
glacier located in the Uttarkashi district of the Garhwal Himalaya, India has received
special attention as it is receding at an alarming rate of 30 m/year. The Gangotri
glacier feeds the Ganges River, which drains nearly 1 million square kilometers of
land surface in India and Bangladesh, and provides water security to half a billion
people. Based on remote sensing data it has been estimated that the overall area of
Gangotri glacier has shrunk by 6% between 1952 and 2006, and that the glacial
terminus has receded by more than 850 m over the past 25 years. However, ground
observation data aimed at studying the changing influence of the Gangotri glacier on
the discharge of the Ganges River are still limited. Here we report preliminary
observations of physical (temperature and conductivity) and chemical (major ion
and trace element concentrations, pH, and dissolved oxygen) parameters of water
samples near glaciated Ganges headwaters for the pre-monsoon (May), monsoon
(August), and post monsoon (November) periods corresponding to 2014. We have
characterized the seasonal δ18O and δ2H variability of the Ganges headwaters. The
pre-monsoonal δ18O varied between -15.1o and -9.3o whereas the monsoonal
δ18O varied between -14.9o and -5.7o. The pre-monsoon δ2H varied between
-105.4o and -61.5o, whereas the monsoonal δ2H varied between -103.8o and
-47.2o. Our isotope-mixing model predicts significant seasonal (pre-monsoon,
monsoon and post-monsoon) variability of glacial melt contributions to the total
discharge. Water chemistry data also shows large variations in chemical characteristics
that are possibly related to variability in flow volume and different source area
contributions. |
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