Search results for "Environmental engineering"
showing 10 items of 2674 documents
Impact de la variabilité climatique et du barrage de Nangbéto sur l'hydrologie du système Mono-Couffo (Afrique de l'Ouest)
2012
Resume En Afrique tropicale, de nombreuses etudes sur la variabilite climatique montrent qu'une tendance a la secheresse s'est manifestee a partir de la fin des annees 1960. Cette secheresse a affecte aussi l'hydrosysteme Mono-Couffo, en Afrique de l'Ouest, avec une persistance remarquable qui s'est repercutee sur les ecoulements. Depuis 1988, avec la mise en eau du barrage de Nangbeto, qui coincide avec une legere reprise pluviometrique dans les annees 1990, on assiste a une modification du regime hydrologique du Mono a Athieme. Les methodes statistiques appliquees aux donnees mensuelles de pluie et debit de la periode 1961–2000 ont permis de constater que les deficits pluviometriques des …
Simulating future trends in hydrological regime of a large Sudano-Sahelian catchment under climate change
2012
Summary This paper assesses the future variability of water resources in the short, medium and long terms over a large Sudano-Sahelian catchment in West Africa. Flow simulations were performed with a daily conceptual model. A period of nearly 50 years (1952–2000) was chosen to capture long-term hydro-climatic variability. Calibration and validation were performed on the basis of a multi-objective function that aggregates a variety of goodness-of-fit indices. The climate models HadCM3 and MPI-M under SRES-A2 were used to provide future climate scenarios over the catchment. Outputs from these models were used to generate daily rainfall and temperature series for the 21st century according to:…
Soil moisture modelling of a SMOS pixel: interest of using the PERSIANN database over the Valencia Anchor Station
2010
In the framework of Soil Moisture and Ocean Salinity (SMOS) Calibration/Validation (Cal/Val) activities, this study addresses the use of the PERSIANN-CCS<sup>1</sup>database in hydrological applications to accurately simulate a whole SMOS pixel by representing the spatial and temporal heterogeneity of the soil moisture fields over a wide area (50×50 km<sup>2</sup>). The study focuses on the Valencia Anchor Station (VAS) experimental site, in Spain, which is one of the main SMOS Cal/Val sites in Europe. <br><br> A faithful representation of the soil moisture distribution at SMOS pixel scale (50×50 km<sup>2</sup>) requires an accurate estimation…
Hydrostratigraphic characterization of glaciofluvial deposits underlying an infiltration basin using ground penetrating radar.
2008
14 pages; International audience; An understanding of the heterogeneity of quaternary gravelly deposits is required to predict flow and contaminant transfer through these formations. In such deposits, preferential flow paths can lead to contamination at depths greater than predicted under the assumption of a homogeneous medium. The difficulties in characterizing their complex structure with conventional methods represent an obstacle for this prediction. In this study, we developed an approach relying on the use of ground penetrating radar (GPR) for the detection of sedimentary depositional units. A genetic interpretation of the radar stratigraphy allowed us to construct a distribution model…
Estimating Profit, Price, and Productivity Changes in Water Industry Using Bennet-Bowley Indicator
2019
AbstractThe assessment of profit, productivity, and price change over time is valuable for regulators and companies when setting tariffs. This paper innovates by comparing profit, price, and produc...
Topographic descriptors and thermal inversions amid the plateaus and mountains of the Jura (France)
2018
Sixteen temperature measurement sites under forest cover are distributed across the plateaus and mountains of the Jura (France). They are composed of pairs of stations located, one at the bottom of a topographic trough, the other at least 50 m higher in altitude. Three descriptors (station elevation, altitudinal difference (amplitude) between the two stations of each site, and topographical context) are used to explain how the frequency, intensity, and duration of inversions are spatially structured. Depending on whether one considers: 1) tn (minimum temperature) or tx (maximum temperature), 2) frequency or intensity, the sign of the correlation values changes. This reflects the fact that n…
Modelling soil moisture at SMOS scale by use of a SVAT model over the Valencia Anchor Station
2010
16 páginas, 9 figuras, 5 tablas.
Identification of processes that control the stable isotope composition of rainwater in the humid tropical West-Central Africa.
2020
12 pages; International audience; This study interprets 11 years (2006 to 2016) and 6 months (March to August in 2017) of respectively monthly and daily isotopic (δD and δ18O) monitoring of rain at Douala (Cameroon), a humid tropical station in Western Africa. The main scope is to analyze the climate controls on precipitation isotopes at different timescales. Firstly, we examine the annual cycles of δ18O. Over the 11 years of survey, the annual cycle exhibits a W shape that is quite reproducible from year to year, with two minima in spring and autumn periods. Based on back trajectory calculations and remote sensing observations of water vapor isotopic composition, we show that the observed …
Bioavailable 87Sr/86Sr in different environmental samples — Effects of anthropogenic contamination and implications for isoscapes in past migration s…
2012
(87)Sr/(86)Sr reference maps (isoscapes) are a key tool for investigating past human and animal migrations. However, there is little understanding of which biosphere samples are best proxies for local bioavailable Sr when dealing with movements of past populations. In this study, biological and geological samples (ground vegetation, tree leaves, rock leachates, water, soil extracts, as well as modern and archeological animal teeth and snail shells) were collected in the vicinity of two early medieval cemeteries ("Thuringians", 5-6th century AD) in central Germany, in order to characterize (87)Sr/(86)Sr of the local biosphere. Animal tooth enamel is not appropriate in this specific context t…
Summarizing the state of the terrestrial biosphere in few dimensions
2020
Abstract. In times of global change, we must closely monitor the state of the planet in order to understand the full complexity of these changes. In fact, each of the Earth's subsystems – i.e., the biosphere, atmosphere, hydrosphere, and cryosphere – can be analyzed from a multitude of data streams. However, since it is very hard to jointly interpret multiple monitoring data streams in parallel, one often aims for some summarizing indicator. Climate indices, for example, summarize the state of atmospheric circulation in a region. Although such approaches are also used in other fields of science, they are rarely used to describe land surface dynamics. Here, we propose a robust method to crea…