Received: 12 Oct 2018 – Accepted for review: 06 Nov 2018 – Discussion started: 07 Nov 2018
Abstract. The strong elevation gradient of the Himalaya allows investigation of altitude and orographic impacts on precipitation isotope values as captured in river samples. This study provides new high-elevation data along a 5000 m gradient collected from rain, snow, and glacial-sourced surface waters and time-series data from April to October 2016 to differentiate the time-variable contributions of source waters to the Arun River. We find nonlinear trends in δ18O and δD lapse rates driven by samples collected at high elevations and a distinct seasonal signal indicative of moisture source influences the surface-water isotope values. Deuterium excess is correlated to snowpack and used to track melt events during the monsoon. Our analysis identifies contributions from snowpack to river discharge before the monsoon onset followed by a 5-week transition to Indian Summer Monsoon-sourced rainfall around mid-June 2016.
This preprint has been withdrawn.
How to cite. Voss, K. A., Bookhagen, B., Sachse, D., and Chadwick, O. A.: Variation of deuterium excess in surface waters across a 5000-m elevation
gradient in the east-central Himalaya, Hydrol. Earth Syst. Sci. Discuss. [preprint], https://doi.org/10.5194/hess-2018-534, 2018.
Water supply in the Himalayas is derived from rainfall, snowpack, glacial melt, and groundwater that vary spatially and seasonally. This study provides new data collected from rain, snow, and glacial-sourced surface waters over a 5000 m elevation range from April to October 2016. We identify water sourced from the summer monsoon versus winter westerly storms and track major snow and glacial melt events to elucidate the sourcing and timing of Himalayan streamflow and inform water management.
Water supply in the Himalayas is derived from rainfall, snowpack, glacial melt, and groundwater...