Analyses of climate change and response of alpine glacier-river runoff in Hailuogou basin, Mount Gongga, China, by using δ2H and δ18O

The climate changes and the associated Hailuogou glacier-river runoff were discussed by analysis of the existing available meteorological and hydrologic data in Hailuogou basin. To better assess the effect of climate change on the stream flow of this river, stable isotope composition was measured on different types of water samples, including meteoric water, stream water, ice-snow melt water and ground water in 2008-2009. The results of this work indicate that: (i) as the annual average temperature in Hailuogou basin rose by 0.5°C in recent 20-years, the mean runoff increased by 2.1% annually. Analyses of meteorological and hydrologic data suggest that changes of the glacier river runoff have responded to climatic fluctuations; (ii) analysis of the measured isotopic data demonstrate that precipitation provides the main part of seasonal variations of runoff of the study river, the effect of change in temperature suggests a linear increase in ice-snow meltwater and total streamflow. (iii) ice-snow meltwater is the main source of this alpine glacier river. Using a δ¹⁸O based hydrologic model, we estimated that the annual contribution of ice-snow meltwater over the total stream flow varied from 81.9% to 85.57% in its upper reach. Quantitative evaluation of the relationship between climate fluctuation and the river runoff is difficult because of the limited available long-term meteorological and hydrologic data in the alpine area in the periphery of the Qinghai-Tibetan Plateau.