Isotope Of Discharge Water From The July 1st Glacier In China
Abstract
Glacier melt water has an important role for water cycle in the arid region, northwest China, since the amount of precipitation in the mountains is much larger than those in the lower desert area. Historically ground water in the desert has been irrigated by meltwater from glaciers and seasonal snow in the mountains. Isotope ratio of the discharge from glaciers provides good information to understand the history of ground water in desert area. The purpose of this study, therefore, is to understand the composition of isotope ratio in the present discharge from glacier taking into account the isotope ratios of the glacier ice and precipitation. Observation has carried out at July 1st Glacier in Qilian mountain, China from June to September in 2002. Sample of the precipitation, discharge water, surface snow and ice on the glacier have been taken to analyzed the delta 18O. We also observed the discharge and mass balance of the glacier. Average delta 18O of the discharge water, precipitation at the altitude 3800 m a.s.l., and glacier surface ice were -10.3 permil, -7.4 permil, -11.4 permil, respectively during the observation period. Altitudinal effect on the delta 18O in the precipitation was -0.16 permil/100m. Older ice, which has accumulated at upper part of the glacier, was exposed at the ablation area at present. delta 18O in the surface ice at ablation area changes from -14.0 permil at the terminal to -10 permil near the equilibrium line altitude, those isotope ratio was smaller than that in the present precipitation falling on the ablation area. We calculated the delta 18O of discharge water by taking into account isotope in rain, snow and melt ice in the ablation area. Calculated result of isotope in discharge was almost equal to the observed delta 18O in the discharge water.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFM.H53A1196S
- Keywords:
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- 1827 Glaciology (1863);
- 1863 Snow and ice (1827)