OBSERVATIONAL STUDY OF MICROPHYSICS IN THE STRATIFORM REGION AND TRANSITION REGION OF A MIDLATITUDE MESOSCALE CONVECTIVE COMPLEX          下载免费PDF全文

Ye Jiadong  Fan Beifen  William R. Cotton  Michael A. Foriune 《Acta Meteorologica Sinica》1991,5(5):527-540

Cloud microphysical data observed with PMS probes have been combined with radar and other in-situdata collected by a NOAA P-3 aircraft that flew through the stratiform and transition regions of a mesoscaleconvective complex(MCC).The combined data have been analyzed with respect to the mescscale structureof the storm systems.The characteristics of ice particles in the transition and stratiform regions were quitediffereat.The ice particle concentrations in the transition region were about 4 to 6 times that found in thestratiform region,and the size of ice particles in the stratiform region was about twice that in the transitionregion.The relatively lower radar reflectivity in the transition region is a result of smaller particle sizes.Themain precipitation particle growth mechanisms are riming and aggregation in the transition region ard theaggregation process predominates in the stratiform region referred from the microphysical structures.The ag-gregation starts in the upper,colder lev(?)ls but becomes more efficient as the particles approach the melting layer.  相似文献   

Textures in deforming forsterite aggregates up to 8 GPa and 1673 K     

Caroline Bollinger  Paul Raterron  Olivier Castelnau  Fabrice Detrez  Sébastien Merkel 《Physics and Chemistry of Minerals》2016,43(6):409-417

We report results from axisymmetric deformation experiments carried out on forsterite aggregates in the deformation-DIA apparatus, at upper mantle pressures and temperatures (3.1–8.1 GPa, 1373–1673 K). We quantified the resulting lattice preferred orientations (LPO) and compare experimental observations with results from micromechanical modeling (viscoplastic second-order self-consistent model—SO). Up to 6 GPa (~185-km depth in the Earth), we observe a marked LPO consistent with a dominant slip in the (010) plane with one observation of a dominant [100] direction, suggesting that [100](010) slip system was strongly activated. At higher pressures (deeper depth), the LPO becomes less marked and more complex with no evidence of a dominant slip system, which we attribute to the activation of several concurrent slip systems. These results are consistent with the pressure-induced transition in the dominant slip system previously reported for olivine and forsterite. They are also consistent with the decrease in the seismic anisotropy amplitude observed in the Earth’s mantle at depth greater than ~200 km.  相似文献   

Three-Dimensional Back-Analysis of an Instrumented Shallow Tunnel Excavated by a Conventional Method     

Mohamed Nabil Houhou  Fabrice Emeriault  Émilie Vanoudheusden 《Geotechnical and Geological Engineering》2016,34(4):1101-1117

The excavation of a shallow tunnel induces deformations of the soil volume in the vicinity and above the tunnel and consequently on the nearby buildings. The range of these deformations depends among other on the geological conditions, the geometry of the tunnel, and the excavation method. In this context, this research focuses on the 3D numerical modeling of a shallow tunnel instrumented during its construction, located on the Toulouse (France) subway line B for which the excavation has been carried out in a conventional manner in an over consolidated molassic geological context. The objective of this analysis is to estimate the tunnel behavior in terms of vertical and horizontal movements of the surrounding soil and the deformations of the existing buildings. The explicit finite differences numerical code FLAC^3D is used to model the various implementation phases of the work where the fluid–soil interaction is taken into account through an undrained coupled analysis. The results of this 3D model are compared to those of the in situ measurements in order to validate the geotechnical characteristics of the molasses. The latter are a useful basis for the back-analysis of the different monitoring sections implemented in areas where the tunnel excavation is made by TBM with pressurized front.  相似文献   

Response of hurricane-type vortices to global warming as simulated by ARPEGE-Climat at high resolution   总被引：1，自引：0，他引：1  

Fabrice Chauvin  Jean-François Royer  Michel Déqué 《Climate Dynamics》2006,27(4):377-399

Atlantic hurricanes and their sensitivity to anthropogenic warming are investigated using very high (0.5°×0.5° over the Atlantic domain) resolution global simulations. The ARPEGE-Climat variable resolution grid demonstrates its usefulness in regional climate studies since resolution can be multiplied by a factor of 2.5 over the domain of interest compared to a uniform grid, for a similar computer cost. The question of hurricane characteristics dependence on anthropogenic warming is tackled trough the implementation of a tracking method. Changes in the total number, as well as locations, of hurricanes appear to depend more on sea surface temperature (SST) spatial patterns anomaly than Atlantic mean intensity, essentially through the change in large scale vertical wind shear. A uniform SST anomaly forcing produces increased and eastward shifted systems while a spatially contrasted anomaly leads to a decrease. Comparison between cyclogenesis density calculated from tracking or large scale combined variables (as a modified Gray parameter) brings some confidence in the use of the latter to investigate low resolution simulations. Mean hurricane dynamical characteristics are weakly changed by the warming but precipitation core and latent heat flux are enhanced in all scenarios.  相似文献   

Characterizing swells in the southern Pacific from seismic and infrasonic noise analyses     

Guilhem Barruol  Dominique Reymond  Fabrice R. Fontaine  Olivier Hyvernaud  Vincent Maurer  Keitapu Maamaatuaiahutapu 《Geophysical Journal International》2006,164(3):516-542

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On the developments of spectral wave models: numerics and parameterizations for the coastal ocean   总被引：1，自引：1，他引：0  

Aron Roland  Fabrice Ardhuin 《Ocean Dynamics》2014,64(6):833-846

The development of numerical wave models for coastal applications, including coupling with ocean circulation models, has spurred an ongoing effort on theoretical foundations, numerical techniques, and physical parameterizations. Some important aspects of this effort are reviewed here, and results are shown in the case of the French Atlantic and Channel coast using version 4.18 of the WAVEWATCH III ^R model. Compared to previous results, the model errors have been strongly reduced thanks to, among other things, the introduction of currents, coastal reflection, and bottom sediment types. This last item is described here for the first time, allowing unprecedented accuracy at some sites along the French Atlantic Coast. The adequate resolution, necessary to represent strong gradients in tidal currents, was made possible by the efficiency brought by unstructured grids. A further increase in resolution, necessary to resolve surf zones and still cover vast regions,will require further developments in numerical methods.  相似文献   

Atmospheric storm surge modeling methodology along the French (Atlantic and English Channel) coast     

Héloïse Muller  Lucia Pineau-Guillou  Déborah Idier  Fabrice Ardhuin 《Ocean Dynamics》2014,64(11):1671-1692

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Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe   总被引：9，自引：2，他引：7  

Elise Delavaud  Fabrice Cotton  Sinan Akkar  Frank Scherbaum  Laurentiu Danciu  Céline Beauval  Stéphane Drouet  John Douglas  Roberto Basili  M. Abdullah Sandikkaya  Margaret Segou  Ezio Faccioli  Nikos Theodoulidis 《Journal of Seismology》2012,16(3):451-473

The Seismic Hazard Harmonization in Europe (SHARE) project, which began in June 2009, aims at establishing new standards for probabilistic seismic hazard assessment in the Euro-Mediterranean region. In this context, a logic tree for ground-motion prediction in Europe has been constructed. Ground-motion prediction equations (GMPEs) and weights have been determined so that the logic tree captures epistemic uncertainty in ground-motion prediction for six different tectonic regimes in Europe. Here we present the strategy that we adopted to build such a logic tree. This strategy has the particularity of combining two complementary and independent approaches: expert judgment and data testing. A set of six experts was asked to weight pre-selected GMPEs while the ability of these GMPEs to predict available data was evaluated with the method of Scherbaum et al. (Bull Seismol Soc Am 99:3234?C3247, 2009). Results of both approaches were taken into account to commonly select the smallest set of GMPEs to capture the uncertainty in ground-motion prediction in Europe. For stable continental regions, two models, both from eastern North America, have been selected for shields, and three GMPEs from active shallow crustal regions have been added for continental crust. For subduction zones, four models, all non-European, have been chosen. Finally, for active shallow crustal regions, we selected four models, each of them from a different host region but only two of them were kept for long periods. In most cases, a common agreement has been also reached for the weights. In case of divergence, a sensitivity analysis of the weights on the seismic hazard has been conducted, showing that once the GMPEs have been selected, the associated set of weights has a smaller influence on the hazard.  相似文献   

The 2013 European Seismic Hazard Model: key components and results   总被引：11，自引：5，他引：6  

Jochen Woessner  Danciu Laurentiu  Domenico Giardini  Helen Crowley  Fabrice Cotton  Gottfried Grünthal  Gianluca Valensise  Ronald Arvidsson  Roberto Basili  Mine Betül Demircioglu  Stefan Hiemer  Carlo Meletti  Roger W. Musson  Andrea N. Rovida  Karin Sesetyan  Massimiliano Stucchi  The SHARE Consortium 《Bulletin of Earthquake Engineering》2015,13(12):3553-3596

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Upscaling of transport processes in porous media with biofilms in non-equilibrium conditions     

Laurent Orgogozo  Fabrice Golfier  Michel Buès  Michel Quintard 《Advances in water resources》2010

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