Variation of deuterium excess in surface waters across a 5000-m elevation gradient in eastern Nepal
- The strong elevation gradient of the Himalaya allows for investigation of altitude and orographic impacts on surface water delta O-18 and delta D stable isotope values. This study differentiates the time- and altitude-variable contributions of source waters to the Arun River in eastern Nepal. It provides isotope data along a 5000-m gradient collected from tributaries as well as groundwater, snow, and glacial-sourced surface waters and time-series data from April to October 2016. We find nonlinear trends in delta O-18 and delta D lapse rates with high-elevation lapse rates (4000-6000 masl) 5-7 times more negative than low-elevation lapse rates (1000-3000 masl). A distinct seasonal signal in delta O-18 and delta D lapse rates indicates time-variable source-water contributions from glacial and snow meltwater as well as precipitation transitions between the Indian Summer Monsoon and Winter Westerly Disturbances. Deuterium excess correlates with the extent of snowpack and tracks melt events during the Indian Summer Monsoon season. OurThe strong elevation gradient of the Himalaya allows for investigation of altitude and orographic impacts on surface water delta O-18 and delta D stable isotope values. This study differentiates the time- and altitude-variable contributions of source waters to the Arun River in eastern Nepal. It provides isotope data along a 5000-m gradient collected from tributaries as well as groundwater, snow, and glacial-sourced surface waters and time-series data from April to October 2016. We find nonlinear trends in delta O-18 and delta D lapse rates with high-elevation lapse rates (4000-6000 masl) 5-7 times more negative than low-elevation lapse rates (1000-3000 masl). A distinct seasonal signal in delta O-18 and delta D lapse rates indicates time-variable source-water contributions from glacial and snow meltwater as well as precipitation transitions between the Indian Summer Monsoon and Winter Westerly Disturbances. Deuterium excess correlates with the extent of snowpack and tracks melt events during the Indian Summer Monsoon season. Our analysis identifies the influence of snow and glacial melt waters on river composition during low-flow conditions before the monsoon (April/May 2016) followed by a 5-week transition to the Indian Summer Monsoon-sourced rainfall around mid-June 2016. In the post-monsoon season, we find continued influence from glacial melt waters as well as ISM-sourced groundwater.…
Verfasserangaben: | Katalyn A. Voss, Bodo BookhagenORCiDGND, Dirk SachseORCiDGND, Oliver A. Chadwick |
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DOI: | https://doi.org/10.1016/j.jhydrol.2020.124802 |
ISSN: | 0022-1694 |
ISSN: | 1879-2707 |
Titel des übergeordneten Werks (Englisch): | Journal of hydrology |
Verlag: | Elsevier |
Verlagsort: | Amsterdam |
Publikationstyp: | Wissenschaftlicher Artikel |
Sprache: | Englisch |
Datum der Erstveröffentlichung: | 13.03.2020 |
Erscheinungsjahr: | 2020 |
Datum der Freischaltung: | 08.11.2023 |
Freies Schlagwort / Tag: | Himalaya; glacier; precipitation; seasonality; snow; stable isotopes |
Band: | 586 |
Aufsatznummer: | 124802 |
Seitenanzahl: | 17 |
Fördernde Institution: | National Science FoundationNational Science Foundation (NSF) [DGE; 1144085]; Robert and Patricia Switzer Foundation; American Geophysical; Union Horton Hydrology Research Grant; ERC Consolidator Grant; (STEEPclim) [647035]; P.E.O. International; UCSB Department of; Geography; UCSB Broom Center for Demography |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften |
Peer Review: | Referiert |