Temporal variability of suspended sediment sources in an alpine catchment combining river/rainfall monitoring and sediment fingerprinting     

Oldrich Navratil  Olivier Evrard  Michel Esteves  Cédric Legout  Sophie Ayrault  Julien Némery  Ainhoa Mate‐Marin  Mehdi Ahmadi  Irène Lefèvre  Alain Poirel  Philippe Bonté 《地球表面变化过程与地形》2012,37(8):828-846

Influence of the rainfall regime on erosion and transfer of suspended sediment in a 905‐km² mountainous catchment of the southern French Alps was investigated by combining sediment monitoring, rainfall data, and sediment fingerprinting (based on geochemistry and radionuclide concentrations). Suspended sediment yields were monitored between October 2007 and December 2009 in four subcatchments (22–713 km²). Automatic sediment sampling was triggered during floods to trace the sediment origin in the catchment. Sediment exports at the river catchment outlet (330 ± 100 t km^‐2 yr^‐1) were mainly driven (80%) by widespread rainfall events (long duration, low intensities). In contrast, heavy, local and short duration storms, generated high peak discharges and suspended sediment concentrations in small upstream torrents. However, these upstream floods had generally not the capacity to transfer the sediment down to the catchment outlet and the bulk of this fine sediment deposited along downstream sections of the river. This study also confirmed the important contribution of black marls (up to 70%) to sediment transported in rivers, although this substrate only occupies c. 10% of the total catchment surface. Sediment exports generated by local convective storms varied significantly at both intra‐ and inter‐flood scales, because of spatial heterogeneity of rainfall. However, black marls/marly limestones contribution remained systematically high. In contrast, widespread flood events that generate the bulk of annual sediment supply at the outlet were characterized by a more stable lithologic composition and by a larger contribution of limestones/marls, Quaternary deposits and conglomerates, which corroborates the results of a previous sediment fingerprinting study conducted on riverbed sediment. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Sediment export from French rivers to the sea     

Magalie Delmas  Olivier Cerdan  Bruno Cheviron  Jean‐Marie Mouchel  Frederique Eyrolle 《地球表面变化过程与地形》2012,37(7):754-762

Knowledge of sediment exports from continental areas is essential for estimating denudation rates and biogeochemical cycles. However, the estimation of current sediment fluxes to the sea is often limited by the availability and quality of sediment discharge data. This study aims to quantify the relative contributions of French rivers to the sediment discharge to the ocean. Sediment fluxes were assessed using the French river quality database, which is characterized by a low temporal resolution but long‐term measurement periods. An improved rating curve approach (IRCA) using daily discharge data, which allows the estimation of mean annual sediment loads from infrequent sediment concentration data, was used to calculate sediment fluxes. The resulting mean annual sediment loads show that French rivers export c. 16.21 Mt yr^‐1 of sediments to the sea. Among the 88 defined French rivers flowing to the sea, the four largest basins (Loire, Rhone, Garonne and Seine) export 13.2 Mt yr^‐1, which corresponds to 81.3% of total exports. No relationship was found between the mass of exported sediment and the size of the drainage basins. This is due to the variety of river basin typologies among these rivers, including lowland rivers in temperate climates, such as the Seine on the one hand and rivers draining mountainous areas in Alpine/Mediterranean areas on the other hand, such as the Rhone. The latter contributes 60% to the total sediment export for France while its drainage area is only 19% of the total area considered. Differences between the river basins considered are also shown by temporal indicators describing the duration of the exports, which may be linked with sediment production processes over drained areas. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

433 Eros lineaments: Global mapping and analysis     

Debra L. Buczkowski  Olivier S. Barnouin-Jha  Louise M. Prockter 《Icarus》2008,193(1):39-52

Using images and laser ranging data from the NEAR-Shoemaker mission, we map lineaments on the surface of Eros in order to investigate the relationship between surface morphology and interior structure. Several sets of lineations are clearly related to visible impact craters, while others suggest that different parts of the asteroid may have undergone different stress histories. Some of these sets infer internal structure, at least on a local level. This structure may derive from Eros' parent body and suggest, although largely coherent, Eros' interior may have portions that have not undergone a common history.  相似文献   

Evaluation of gene expression programming approaches for estimating daily evaporation through spatial and temporal data scanning   总被引：1，自引：0，他引：1       下载免费PDF全文

Jalal Shiri  Pau Marti  Vijay P. Singh 《水文研究》2014,28(3):1215-1225

Evaporation of water from free water surfaces or from land surfaces is one of the main components of the hydrological cycle, and its occurrence is governed by various meteorological and physical factors. There is a multitude of models developed for estimating daily evaporation values by using weather data. This paper evaluates a Gene Expression Programming (GEP) model for estimating evaporation through spatial and temporal data scanning techniques. It is by using ‘leave‐one‐out’ procedures, a complete scan of the possible train and test set configurations is carried out according to temporal and spatial criteria. Comparison of the GEP model with empirical‐physical models shows that daily evaporation values computed by the GEP model are more accurate. Further, local calibration of the GEP model may not be needed, if enough climatic data are available at other stations. The performance of the GEP model fluctuates throughout the period of study and between stations. A suitable assessment of the model should consider a complete temporal and/or spatial scan of the data set used. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Development and application of a conceptual hydrologic model to predict soil salinity within modern Tunisian oases     

Brahim Askri  Rachida Bouhlila  Jean Olivier Job 《Journal of Hydrology》2010,380(1-2):45-61

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Comparison of Oil Transmissivity Methods Using Bail‐Down Test Data          下载免费PDF全文

Cédric Palmier  Matthew Dodt  Olivier Atteia 《Ground Water Monitoring & Remediation》2016,36(3):73-83

This paper evaluates the results from three methods commonly used to estimate oil transmissivity: the modified Cooper solution (Beckett and Lyverse 2002), the modified Bouwer and Rice method (Kirkman 2013), and the modified Jacob and Lohman method (Huntley 2000). Determining the validity of oil transmissivity values is important (e.g., when used in extraction system design and operation) and not straightforward as these methods are based on different assumptions and boundary conditions and introduce different simplifying assumptions to allow for estimating oil drawdown. Data from 289 bail‐down tests performed during an oil remediation project were used in this evaluation. Analysis of these tests produced realistic transmissivity values and good correlation between these three methods, giving the authors confidence in the oil transmissivity values as this correlation is reflected across a significant number of data sets. Secondly, the nature of oil and water recharge to the wells interpreted from Kirkman's J‐ratio values largely validates the Huntley (2000) simplifying assumption that the potentiometric surface will be relatively constant during the test, allowing the use of the modified Bouwer and Rice method. Finally, the impact of oil extraction on measured oil thickness and estimated oil transmissivity was also assessed. The study showed a clear general decrease in both measured oil thicknesses and estimated oil transmissivity during the oil recovery project. However, measured oil thickness and estimated oil transmissivity are not clearly correlated, and, as a consequence, the range of decrease in one parameter does not allow any prediction of the range of decrease in the second parameter.  相似文献   

Eruptive parameters and dynamics of the April 2015 sub-Plinian eruptions of Calbuco volcano (southern Chile)     

Angelo Castruccio  Jorge Clavero  Andrea Segura  Pablo Samaniego  Olivier Roche  Jean-Luc Le Pennec  Bárbara Droguett 《Bulletin of Volcanology》2016,78(9):62

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Meteoric ions in the atmosphere of Mars   总被引：1，自引：0，他引：1  

Gregorio J. Molina-Cuberos  Olivier Witasse 《Planetary and Space Science》2003,51(3):239-249

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Search for 248Cm in the early Solar System     

B. Lavielle  K. Marti  P. Pellas  C. Perron 《Meteoritics & planetary science》1992,27(4):382-386

Abstract— Possible evidence for the presence of ²⁴⁸Cm in the early Solar System was reported from fission gas studies (Rao and Gopalan, 1973) and recently from studies of very high nuclear track densities (≥ 5 × 10^g cm^?2) in the merrillite of the H4 chondrite Forest Vale (F. V.) (Pellas et al., 1987). We report here an analysis of the isotopic abundances of xenon in F. V. phosphates and results of track studies in phosphate/pyroxene contacts. The fission xenon isotopic signature clearly identifies ²⁴⁴Pu as the extinct progenitor. We calculate an upper limit ²⁴⁸Cm/²⁴⁴Pu < 1.5 × 10^?3 at the beginning of Xe retention in F. V. phosphates. This corresponds to an upper limit of the ratio ²⁴⁸Cm/²³⁵U ≤ 5 × 10^?5, further constraining the evidence for any late addition of freshly synthesized actinide elements just prior to Solar System formation. The fission track density observed after annealing the phosphates at 290 °C (1 hr, which essentially erases spallation recoil tracks) is also in agreement with the ²⁴⁴Pu abundance inferred from fission Xe. The spallation recoil tracks produced during the 76 Ma cosmic-ray exposure account for the very high track density in merrillites.  相似文献   

On244Pu in lunar rocks from Fra Mauro and implications regarding their origin     

K. Marti  B. D. Lightner  G. W. Lugmair 《Earth, Moon, and Planets》1973,8(1-2):241-250

The evidence forin situ produced fission xenon from²⁴⁴Pu in rock 14321 is presented. The inferred abundance ratio²⁴⁴Pu/²³⁸U is found to be consistent with values observed in a meteorite. Data from a stepwise release of the xenon permits a characterization of the trapped component, which can be shown to be distinct from solar xenon. We discuss the evidence for the presence of fission gases and of uncorrelated radiogenic argon in this and in other Apollo 14 rocks and some implications regarding their origin.Paper dedicated to Prof. Harold C. Urey on the occasion of his 80th birthday on 29 April 1973.  相似文献