气候变化领域集成服务门户(CCPortal): Temperature signal in suspended sediment export from an Alpine catchment

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DOI	10.5194/hess-22-509-2018
	Temperature signal in suspended sediment export from an Alpine catchment
	Costa A.; Molnar P.; Stutenbecker L.; Bakker M.; Silva T.A.; Schlunegger F.; Lane S.N.; Loizeau J.-L.; Girardclos S.
发表日期	2018
ISSN	1027-5606
起始页码	509
结束页码	528
卷号	22 期号:1
英文摘要	Suspended sediment export from large Alpine catchments (> 1000 km2) over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation-deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity), and the activation of different potential sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment concentration through hillslope erosion by rainfall on snow-free surfaces, and increased meltwater production on snow-free glacier surfaces. Despite the rise in air temperature, changes in mean discharge in the mid-1980s were not statistically significant, and their interpretation is complicated by hydropower reservoir management and the flushing operations at intakes. Overall, the results show that to explain changes in suspended sediment transport from large Alpine catchments it is necessary to include an understanding of the multitude of sediment sources involved together with the hydroclimatic conditioning of their activation (e.g. changes in precipitation, runoff, air temperature). In addition, this study points out that climate signals in suspended sediment dynamics may be visible even in highly regulated and human-impacted systems. This is particularly relevant for quantifying climate change and hydropower impacts on streamflow and sediment budgets in Alpine catchments. © 2018 Author(s).
语种	英语
scopus关键词	Air intakes; Atmospheric temperature; Budget control; Catchments; Chemical activation; Climate change; Crystallography; Hydroelectric power; Ice; Precipitation (meteorology); Rain; Reservoir management; Reservoirs (water); Runoff; Sediment transport; Sedimentation; Sediments; Snow; Snow melting systems; Anthropogenic impacts; Hydropower reservoirs; Mean air temperatures; Sediment availability; Step-like increase; Suspended sediment concentrations; Suspended sediment yields; Temperature signal; Suspended sediments; air temperature; alpine environment; anthropogenic effect; catchment; climate change; climate conditions; discharge; glacier; meltwater; precipitation (climatology); rainfall; sediment budget; sediment transport; snow cover; snowmelt; streamflow; suspended sediment; Rhone Basin
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160142
作者单位	Costa, A., Institute of Environmental Engineering, ETH Zurich, Zurich, 8093, Switzerland; Molnar, P., Institute of Environmental Engineering, ETH Zurich, Zurich, 8093, Switzerland; Stutenbecker, L., Institute of Applied Geosciences, Technische Universität Darmstadt, Darmstadt, Germany; Bakker, M., Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, 1015, Switzerland; Silva, T.A., Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Geneva, 1211, Switzerland; Schlunegger, F., Institute of Geological Sciences, University of Bern, Bern, 3012, Switzerland; Lane, S.N., Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, 1015, Switzerland; Loizeau, J.-L., Department F.-A. Forel for Environmental and Aquatic Sciences, University of Geneva, Geneva, 1211, Switzerland; Girardclos, S., Department of Earth Sciences and Institute for Environmental Sciences, University of Geneva, Geneva, 1205, Switzerland
推荐引用方式 GB/T 7714	Costa A.,Molnar P.,Stutenbecker L.,et al. Temperature signal in suspended sediment export from an Alpine catchment[J],2018,22(1).
APA	Costa A..,Molnar P..,Stutenbecker L..,Bakker M..,Silva T.A..,...&Girardclos S..(2018).Temperature signal in suspended sediment export from an Alpine catchment.Hydrology and Earth System Sciences,22(1).
MLA	Costa A.,et al."Temperature signal in suspended sediment export from an Alpine catchment".Hydrology and Earth System Sciences 22.1(2018).