Littoral '92     

H. Flanquart  C. Meur-Férec  Ph. Deboudt  V. Morel  A.-P. Hellequin  et al. 《GeoJournal》1991,24(2):223-223

Reports

Littoral '92  相似文献   

Ocean tide loading (OTL) displacements from global and local grids: comparisons to GPS estimates over the shelf of Brittany, France   总被引：1，自引：0，他引：1  

Stavros A. Melachroinos  R. Biancale  M. Llubes  F. Perosanz  F. Lyard  M. Vergnolle  M. -N. Bouin  F. Masson  J. Nicolas  L. Morel  S. Durand 《Journal of Geodesy》2008,82(6):357-371

In this paper we examine OTL displacements detected by GPS stations of a dedicated campaign and validate ocean tide models. Our area of study is the continental shelf of Brittany and Cotentin in France. Brittany is one of the few places in the world where tides provoke loading displacements of ∼10–12 cm vertically and a few cm horizontally. Ocean tide models suffer from important discrepancies in this region. Seven global and regional ocean tide models were tested: FES2004 corrected for K2, TPXO.7.0, TPXO.6.2, GOT00.2, CSR4.0, NAO.99b and the most recent regional grids of the North East Atlantic (NEA2004). These gridded amplitudes and phases of ocean tides were convolved in order to get the predicted OTL displacements using two different algorithms. Data over a period of 3.5 months of 8 GPS campaign stations located on the north coast of Brittany are used, in order to evaluate the geographical distribution of the OTL effect. We have modified and implemented new algorithms in our GPS software, GINS 7.1. GPS OTL constituents are estimated based on 1-day batch solutions. We compare the observed GPS OTL constituents of M₂, S₂, N₂ and K₁ waves with the selected ocean tide models on global and regional grids. Large phase-lag and amplitude discrepancies over 20° and 1.5 cm in the vertical direction in the semi-diurnal band of M₂ between predictions and GPS/models are detected in the Bay of Mont St-Michel. From a least squares spectral analysis of the GPS time-series, significant harmonic peaks in the integer multiples of the orbital periods of the GPS satellites are observed, indicating the existence of multipath effects in the GPS OTL constituents. The GPS OTL observations agree best with FES2004, NEA2004, GOT00.2 and CSR4.0 tide models.  相似文献   

Modeling the 2D behavior of dry‐stone retaining walls by a fully discrete element method          下载免费PDF全文

James J. Oetomo  Eric Vincens  Fabian Dedecker  Jean‐Claude Morel 《国际地质力学数值与分析法杂志》2016,40(7):1099-1120

The dry‐stone retaining walls (DSRW) have been tipped as a promising solution for sustainable development. However, before recently, their behavior is relatively obscure. In this study, discrete element method (DEM) approach was applied to simulate the plane strain failure of these walls. A commercial DEM package (PFC2D™) was used throughout this study. The authors used a fully discrete approach; thus, both the wall and the backfill were modeled as discrete elements. The methodology for obtaining the micromechanical parameters was discussed in detail; this includes the three mechanical sub‐systems of DSRWs: wall, backfill and interface. The models were loaded progressively until failure, and then the results were compared with the full‐scale experimental results where the walls were loaded, respectively, with hydrostatic load and backfill. Despite its complexity and its intensive calculation time, DEM model can then be used to validate a more simplified approach. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Ekman drift and vortical structures     

Yves Morel  Leif N. Thomas   《Ocean Modelling》2009,27(3-4):185-197

In this article, the authors study the influence of a constant wind on the displacement of a vortex. The well known Ekman current develops in the surface layer and is responsible for a transport perpendicular to the wind: the Ekman drift.An additional process is, however, evidenced, whose importance is as strong as the Ekman drift. There indeed exists a curl of the wind-driven acceleration along isopycnic surfaces when they are spatially variable (they enter and leave the depth where the wind stress acts), which generates potential vorticity anomalies. This diabatic effect is shown to generate potential vorticity anomalies which acts on the propagation of vortical waves and non linear vortices.It is shown that this effect drastically reduces the effect of the Ekman drift for linear waves and surface intensified vortices, while extending its effect to subsurface vortices. It also generates along wind propagation, whose sign depends on the vortex characteristics.  相似文献   

Adaptation of the vertical resolution in the mixed layer for HYCOM   总被引：1，自引：0，他引：1  

Ccile Renaudie  Rmy Baraille  Yves Morel  Gwenaëlle Hello  Herv Giordani 《Ocean Modelling》2009,30(2-3):178-189

This paper focuses on the dynamics of the mixed layer. When the mixed layer depth increases, the vertical discretisation eventually becomes too sparse at the bottom of this layer to accurately resolve its evolution and strong numerical errors can appear. This is linked to the fact that the vertical resolution is concentrated in the upper part of the ocean and does not adapt to the deepening of the mixed layer.Knowing that the HYbrid Coordinate Ocean Model (HYCOM) is able to modify the distribution of the vertical levels, we suggest in this paper a method to adapt the resolution to the mixed layer extension. This method is tested in 1-D configurations for two academic atmospheric forcing conditions (strong convection and wind-mixing) and a realistic forcing extending over one year, with seasonal restratification following strong winter convection. The new method improves the results in all cases, and in particular when the mixed layer reaches deep layers.  相似文献   

A field comparison of two methods for the determination of copper complexation: Bacterial bioassay and fixed-potential amperometry     

Janet G. Hering  William G. Sunda  Randolph L. Ferguson  Francois M.M. Morel 《Marine Chemistry》1987,20(4)

Complexation of copper added to seawater was determined by bacterial bioassay and fixedpotential amperometry. Consistent results were obtained by these two fundamentally different methods. The results of this study support the validity of both techniques and the field applicability of fixed-potential amperometry.The intercomparison studies were performed on samples collected at the N.Y.C. sewage sludge dumpsite and in relatively unpolluted coastal waters. In this limited study, the calculated free cupric ion concentrations at ambient total copper concentrations were similar at both sites.  相似文献   

Routine Analyses of Trace Elements in Geological Samples using Flow Injection and Low Pressure On-Line Liquid Chromatography Coupled to ICP-MS: A Study of Geochemical Reference Materials BR, DR-N, UB-N, AN-G and GH   总被引：6，自引：0，他引：6  

Jean Carignan  Pascal Hild  Guy Mevelle  Jacques Morel  Delphine Yeghicheyan 《Geostandards and Geoanalytical Research》2001,25(2-3):187-198

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Aged anthropogenic iodine in a boreal peat bog     

S. Maillant  M.I. Sheppard  G. Echevarria  S. Denys  G. Villemin  P. Tekely  E. Leclerc-Cessac  J.L. Morel 《Applied Geochemistry》2007

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Five-year bio-monitoring of aquatic ecosystems near Artigas Antarctic Scientific Base,King George Island     

Mara A Morel  Victoria Braa  Cecilia Martnez-Rosales  Clica Cagide  Susana Castro-Sowinski 《极地研究(英文版)》2015,(1)

Fildes Peninsula, in King George Island, Antarctica, has a great concentration of international facilities, and it has clearly been affected by human activities. The objective of this 5-year study was ...  相似文献   

Exotic ion H 3 ++ in strong magnetic fields     

Juan C. López Vieyra  Alexander V. Turbiner  Nicolais L. Guevara 《Astrophysics and Space Science》2007,308(1-4):493-497

1. The exotic system H ₃ ⁺⁺ (which does not exist without magnetic field) exists in strong magnetic fields:
   1. In triangular configuration for B≈10⁸–10¹¹?G (under specific external conditions)
   2. In linear configuration for B>10¹⁰?G
2. In the linear configuration the positive z-parity states 1σ _g , 1π _u , 1δ _g are bound states
3. In the linear configuration the negative z-parity states 1σ _u , 1π _g , 1δ _u are repulsive states
4. The H ₃ ⁺⁺ molecular ion is the most bound one-electron system made from protons at B>3×10¹³?G

Possible application: The H ₃ ⁺⁺ molecular ion may appear as a component of a neutron star atmosphere under a strong surface magnetic field B=10¹²–10¹³?G.  相似文献