Emmanuel Ledoux

Bio: Emmanuel Ledoux is an academic researcher from Mines ParisTech. The author has contributed to research in topics: Aquifer & Groundwater. The author has an hindex of 30, co-authored 90 publications receiving 3311 citations. Previous affiliations of Emmanuel Ledoux include Pierre-and-Marie-Curie University & Centre national de la recherche scientifique.

Modeling fracture flow with a stochastic discrete fracture network: calibration and validation: 1. The flow model

Abstract: A large-scale investigation of fracture flow was recently conducted in a granite uranium mine at Fanay-Augeres, France. Its aim was to develop a methodology for the investigation of possible nuclear waste repository sites in crystalline environments, and thus to determine what measurements to make and what models to use in order to predict the flow and transport properties of the medium, i.e., their average behaviors and spatial variabilities at different scales. Four types of data were collected: (1) geometry of the fracture network; (2) local hydraulic properties measured by injection tests in boreholes; (3) global hydraulic behavior from flow rate and piezometric head distribution at a 106 m3 scale; and (4) tracer tests performed at a scale of up to 40 m. A stochastic fracture network model assuming negligible matrix permeability was developed and calibrated essentially on data 1 and 2 above; this was then used to predict data 3 and 4 in an attempt to validate both the parameters and the structure of the model. In this first part, only the flow problem (data 1) is discussed.

Modeling fracture flow with a stochastic discrete fracture network: Calibration and validation: 2. The transport model

Abstract: As part of the development of a methodology for investigating flow and transport in fractured rocks, a large-scale experiment was recently performed at Fanay-Augeres, France. In a companion paper (Cacas et al., this issue) (paper 1) the results of the flow measurements were analyzed. In this paper, the results of the tracer experiments are interpreted. A particle following is coupled to the flow model, described in paper 1. Microscopic dispersion in the fractures and retardation effects due to unevenness of the flow paths are taken into account. The transport model is calibrated on in situ tracer tests, whereas the parameters of the hydraulic model were initially fitted on structural and hydraulic measurements (paper 1). The dispersive properties of the model are reasonably comparable to those of the real site. It tends to confirm the validity of the preliminary hydraulic calibration of the model and thus to validate further the approach used to simulate hydraulic and transport phenomena.

The CNRM-CM5.1 global climate model: description and basic evaluation

Abstract: A new version of the general circulation model CNRM-CM has been developed jointly by CNRM-GAME (Centre National de Recherches Meteorologiques—Groupe d’etudes de l’Atmosphere Meteorologique) and Cerfacs (Centre Europeen de Recherche et de Formation Avancee) in order to contribute to phase 5 of the Coupled Model Intercomparison Project (CMIP5). The purpose of the study is to describe its main features and to provide a preliminary assessment of its mean climatology. CNRM-CM5.1 includes the atmospheric model ARPEGE-Climat (v5.2), the ocean model NEMO (v3.2), the land surface scheme ISBA and the sea ice model GELATO (v5) coupled through the OASIS (v3) system. The main improvements since CMIP3 are the following. Horizontal resolution has been increased both in the atmosphere (from 2.8° to 1.4°) and in the ocean (from 2° to 1°). The dynamical core of the atmospheric component has been revised. A new radiation scheme has been introduced and the treatments of tropospheric and stratospheric aerosols have been improved. Particular care has been devoted to ensure mass/water conservation in the atmospheric component. The land surface scheme ISBA has been externalised from the atmospheric model through the SURFEX platform and includes new developments such as a parameterization of sub-grid hydrology, a new freezing scheme and a new bulk parameterisation for ocean surface fluxes. The ocean model is based on the state-of-the-art version of NEMO, which has greatly progressed since the OPA8.0 version used in the CMIP3 version of CNRM-CM. Finally, the coupling between the different components through OASIS has also received a particular attention to avoid energy loss and spurious drifts. These developments generally lead to a more realistic representation of the mean recent climate and to a reduction of drifts in a preindustrial integration. The large-scale dynamics is generally improved both in the atmosphere and in the ocean, and the bias in mean surface temperature is clearly reduced. However, some flaws remain such as significant precipitation and radiative biases in many regions, or a pronounced drift in three dimensional salinity.

River Discharge to the Coastal Ocean: A Global Synthesis

Abstract: Foreword 1. Introduction 2. Runoff, erosion and delivery to the coastal ocean 3. Temporal variations 4. Human impacts Appendices. Global River Database: Appendix A: North and Central America Appendix B: South America Appendix C: Europe Appendix D: Africa Appendix E: Eurasia Appendix F: Asia Appendix G: Oceania References Index.