DOI: 10.5194/hess-20-1599-2016
Scopus记录号: 2-s2.0-84966335412
论文题名: Hydrological, chemical, and isotopic budgets of Lake Chad: A quantitative assessment of evaporation, transpiration and infiltration fluxes
作者: Bouchez C ; , Goncalves J ; , Deschamps P ; , Vallet-Coulomb C ; , Hamelin B ; , Doumnang J ; -C ; , Sylvestre F
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2016
卷: 20, 期: 4 起始页码: 1599
结束页码: 1619
语种: 英语
Scopus关键词: Aquifers
; Budget control
; Evaporation
; Infiltration
; Isotopes
; Lakes
; Reservoirs (water)
; Transpiration
; Chemical simulations
; Climate variability
; Hydrological budgets
; Hydrological changes
; Infiltration fluxes
; Quantitative assessments
; Quaternary aquifers
; Relative contribution
; Evapotranspiration
; aquifer
; climate change
; evaporation
; evapotranspiration
; hydrological change
; infiltration
; isotopic analysis
; quantitative analysis
; transpiration
; Lake Chad
; Sahel [Sub-Saharan Africa]
英文摘要: In the Sahelian belt, Lake Chad is a key water body for 13 million people, who live on its resources. It experiences, however, substantial and frequent surface changes. Located at the centre of one of the largest endorheic basins in the world, its waters remain surprisingly fresh. Its low salinity has been attributed to a low infiltration flow whose value remains poorly constrained. Understanding the lake's hydrological behaviour in response to climate variability requires a better constraint of the factors that control its water and chemical balance. Based on the three-pool conceptualization of Lake Chad proposed by Bader et al. (2011), this study aims to quantify the total water outflow from the lake, the respective proportions of evaporation (E), transpiration (T), and infiltration (I), and the associated uncertainties. A Bayesian inversion method based on lake-level data was used, leading to total water loss estimates in each pool (E + T + I = TI). Sodium and stable isotope mass balances were then used to separate total water losses into E, T, and I components. Despite the scarcity of representative data available on the lake, the combination of these two geochemical tracers is relevant to assess the relative contribution of these three outflows involved in the control of the hydrological budget. Mean evapotranspiration rates were estimated at 2070±100 and 2270±100mmg yr-1 for the southern and northern pools, respectively. Infiltration represents between 100 and 300mmyr-1 but most of the water is evapotranspirated the first few kilometres from the shorelines and does not efficiently recharge the Quaternary aquifer. Transpiration is shown to be significant, around 300mmyr-1 and reaches 500mmyr-1 in the vegetated zone of the archipelagos. Hydrological and chemical simulations reproduce the marked hydrological change between the normal lake state that occurred before 1972 and the small lake state after 1972 when the lake surface shrunk to a one-tenth of its size. According to our model, shrinking phases are efficient periods for salt evacuation from the lake towards the phreatic aquifer. © Author(s) 2016. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78862
Appears in Collections: 气候变化事实与影响
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作者单位: CEREGE UM34, Aix-Marseille Université, CNRS, IRD, Collège de France, Aix en Provence, France; Laboratoire de Géologie, Géomorphologie et Télédétection, Faculté des Sciences Exactes et Appliquées, Université de NDjaména, NDjaména, Chad
Recommended Citation:
Bouchez C,, Goncalves J,, Deschamps P,et al. Hydrological, chemical, and isotopic budgets of Lake Chad: A quantitative assessment of evaporation, transpiration and infiltration fluxes[J]. Hydrology and Earth System Sciences,2016-01-01,20(4)