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1.
Claudia Rossano Simone Gambineri Lucia Fanini Virginie Durier Colette Rivault Felicita Scapini 《Estuarine, Coastal and Shelf Science》2009
The aim of the present study was to test sun orientation and rhythmic activity of two sandhopper populations from two Atlantic macro-tidal beaches. A population from Le Verger beach (orientated to 346°, Ille et Vilaine, Brittany, France) and a population from Damgan (orientated to 195°, Morbihan, Brittany, France), were tested on the beach under clear sky discriminating for landscape vision. For both populations locomotor activity rhythm was recorded in the laboratory. The two beaches differed for climatic features, tidal range and for human use. Both talitrid populations resulted very well orientated toward the shoreline, and both used solar position and landscape vision to orient. However the multiple regression analysis of orientation with climatic features showed a different use of local cues by the two populations and a slight influence of tidal regime (ebbing and rising tide), in spite of the supralittoral zonation of sandhoppers. In the laboratory they showed a well defined rhythmic behaviour as well as a bimodal rhythmicity, explained as a tidal one. These results are a new brick in the complex picture of orientation and rhythm studies on sandy beach invertebrates. 相似文献
2.
Lies Loncke Virginie Gaullier Laurence Droz Emmanuelle Ducassou Sébastien Migeon Jean Mascle 《Marine and Petroleum Geology》2009,26(5):633-646
The Nile deep-sea fan (NDSF), turbiditic system reaching a size of about 90,000 km2, has been investigated since 1998 by several geophysical methods (multibeam bathymetry, backscatter imagery, seismic data, 3–5 kHz echo-sounding). The analysis of this important data set evidenced that the NDSF is the locus of numerous multi-scale slope instabilities. Three main types of instabilities have been defined, mainly on the basis of their size or origin. (1) First type of instabilities related to the generalized gravity spreading of the Plio-Quaternary deep-sea fan on Messinian salt layers. This global spreading is accommodated by numerous localized slides. (2) Second type of instabilities correspond to giant mass movements probably triggered either by earthquakes, fluids, or climate and eustatic oscillations. Finally, (3) third type of instabilities correspond either to localized levee liquefactions or to thin-skinned slides on the steep slopes of the Eratosthenes seamount. The deposits generated by these slope movements greatly participate in the building of the NDSF. The characterization of these different instabilities, in a petroleum province as the NDSF, has important implications in terms of risk assessments when considering drilling operations. 相似文献
3.
Real-time multi-model decadal climate predictions 总被引：1，自引：1，他引：0
Doug M. Smith Adam A. Scaife George J. Boer Mihaela Caian Francisco J. Doblas-Reyes Virginie Guemas Ed Hawkins Wilco Hazeleger Leon Hermanson Chun Kit Ho Masayoshi Ishii Viatcheslav Kharin Masahide Kimoto Ben Kirtman Judith Lean Daniela Matei William J. Merryfield Wolfgang A. Müller Holger Pohlmann Anthony Rosati Bert Wouters Klaus Wyser 《Climate Dynamics》2013,41(11-12):2875-2888
We present the first climate prediction of the coming decade made with multiple models, initialized with prior observations. This prediction accrues from an international activity to exchange decadal predictions in near real-time, in order to assess differences and similarities, provide a consensus view to prevent over-confidence in forecasts from any single model, and establish current collective capability. We stress that the forecast is experimental, since the skill of the multi-model system is as yet unknown. Nevertheless, the forecast systems used here are based on models that have undergone rigorous evaluation and individually have been evaluated for forecast skill. Moreover, it is important to publish forecasts to enable open evaluation, and to provide a focus on climate change in the coming decade. Initialized forecasts of the year 2011 agree well with observations, with a pattern correlation of 0.62 compared to 0.31 for uninitialized projections. In particular, the forecast correctly predicted La Niña in the Pacific, and warm conditions in the north Atlantic and USA. A similar pattern is predicted for 2012 but with a weaker La Niña. Indices of Atlantic multi-decadal variability and Pacific decadal variability show no signal beyond climatology after 2015, while temperature in the Niño3 region is predicted to warm slightly by about 0.5 °C over the coming decade. However, uncertainties are large for individual years and initialization has little impact beyond the first 4 years in most regions. Relative to uninitialized forecasts, initialized forecasts are significantly warmer in the north Atlantic sub-polar gyre and cooler in the north Pacific throughout the decade. They are also significantly cooler in the global average and over most land and ocean regions out to several years ahead. However, in the absence of volcanic eruptions, global temperature is predicted to continue to rise, with each year from 2013 onwards having a 50 % chance of exceeding the current observed record. Verification of these forecasts will provide an important opportunity to test the performance of models and our understanding and knowledge of the drivers of climate change. 相似文献
4.
The influence of a hedge surrounding bottomland on soil‐water movement along the hillslope was studied on a plot scale for 28 months. The study was based on the comparison of two transects, one with a hedge, the other without, using mainly a dense grid of tensiometers. The influence of the bottomland hedge was located in the area where tree roots were developed, several metres upslope from the hedge, and could be observed both in the saturated and non‐saturated zone, from May to December. The hedge induced a high rate of soil drying, because of the high evaporative capacity of the trees. We evaluated that water uptake by the hedge during the growing season was at least 100 mm higher than without a hedge. This increased drying rate led to a delayed rewetting of the soils upslope from the hedge in autumn, of about 1 month compared with the situation without a hedge. Several consequences of this delayed rewetting are expected: a delay in the return of subsurface transfer from the hillslope to the riparian zone, a buffering effect of hedges on floods, already observed at the catchment scale, and an increased residence time of pollutants. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
5.
The Islands of Réunion and Mayotte are French territories in the Indian Ocean and are prone to numerous and recurrent hazards
as well as to increasing vulnerabilities. This paper examines disaster risk reduction on non-sovereign islands through the
case studies of Réunion and Mayotte. The approach used is embedded in standard geographical approaches to risk analysis, focusing
on place-based vulnerability, in order to understand disaster risk and disaster risk reduction on both islands. In addition
to establishing baseline information and visiting both islands for further data, 21 semi-structured individual interviews
were completed to understand the people’s perceptions of the hazards and of their vulnerabilities. Disaster risk reduction
strategies, and attitudes from governing bodies implementing the strategies, tend to assume similar vulnerability contexts
as mainland France, despite obvious differences on the islands. Many policies are implemented in a top–down manner by those
from mainland France who have little interest in, and who do not fully take into consideration, local realities. This paper
contributes new case studies to the literature, especially in comparing two non-Anglophone non-sovereign islands, and reinforces
recommendations factoring in local contexts when addressing ‘vulnerability of a place’ to disasters. 相似文献
6.
Virginie Guemas David Salas-Mélia Masa Kageyama Hervé Giordani Aurore Voldoire Emilia Sanchez-Gomez 《Climate Dynamics》2010,34(4):527-546
This study aims at understanding the summer ocean-atmosphere interactions in the North Atlantic European region on intraseasonal
timescales. The CNRMOM1d ocean model is forced with ERA40 (ECMWF Re-Analysis) surface fluxes with a 1-h frequency in solar
heat flux (6 h for the other forcing fields) over the 1959–2001 period. The model has 124 vertical levels with a vertical
resolution of 1 m near the surface and 500 m at the bottom. This ocean forced experiment is used to assess the impact of the
North Atlantic weather regimes on the surface ocean. Composites of sea surface temperature (SST) anomalies associated with
each weather regime are computed and the mechanisms explaining these anomalies are investigated. Then, the SST anomalies related
to each weather regime in the ocean-forced experiment are prescribed to the ARPEGE Atmosphere General Circulation Model. We
show that the interaction with the surface ocean induces a positive feedback on the persistence of the Blocking regime, a
negative feedback on the persistence of the NAO-regime and favours the transition from the Atlantic Ridge regime to the NAO-regime
and from the Atlantic Low regime toward the Blocking regime. 相似文献
7.
8.
Low-frequency current fluctuations in the deep central equatorial Atlantic are analyzed using current meter measurements recorded
from November 1992 to November 1994. Current meters were located at about 14°W of longitude and 1° of latitude on both sides
of the equator between 1,700 m depth and the ocean bottom. At all sampling depths, the velocity fluctuations are dominantly
zonal and symmetrical with respect to the equator. At 1,700 and 2,000 m, the flow is dominated by annual period fluctuations,
at 3,000 m, the velocity field amplitude presents a minimum, and at 3,750 and 3,950 m, the flow is modulated by annual and
semiannual period variability. The annual signal exhibits an apparent upward phase propagation. When considering the phase
and the amplitude of the seasonal fluctuations, the data compare well with the outputs of a realistic numerical simulation
of the Atlantic Ocean. Together with a previous analysis of the model simulations, this supports the idea that the observed
annual fluctuations are due to wind-forced vertically propagating Kelvin and Rossby waves. Data and model do not provide deciding
evidences of the presence of semiannual equatorial waves deeper than 3,500 m depth in the central equatorial Atlantic Ocean. 相似文献
9.
Virginie Mamadouh 《GeoJournal》1999,47(3):477-486
Differences between the national political cultures of the European states are puzzling. They are too often taken for granted
or treated as an elusive explanation for residual differences that can not be accounted for in comparative politics. Here
they are put at the core of a comparative analysis. This article explores the origins of differences between national political
cultures. It deals with national political cultures from the perspective of Cultural Theory or grid-group analysis. A national
political culture is conceived as a ‘conversation’ between subcultures associated to national political institutions and practices
(and not as an aggregated pattern of individual orientations toward political objects). National political cultures can be
characterised on the basis of ideal typical patterns of relations between the basic cultures or rationalities distinguished
by Cultural Theory. After an assessment of the differences between the national political cultures of the Member States of
the European Union, the paper considers traditional family structures as possible sources of differentiation, elaborating
upon the work of the French political historian Emmanuel Todd who has documented the correspondence between the geography
of traditional family structures and the geography of ideologies in Europe.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
Martine D. Buatier Brice Lacroix Pierre Labaume Virginie Moutarlier Delphine Charpentier Jean Pierre Sizun Anna Travé 《Swiss Journal of Geoscience》2012,105(2):313-324
Thrusting fault zone in foreland basins are characterized by highly foliated zones generally enriched in phyllosilicates which can play a major role on the mechanical behaviour of the fault. In this context, investigations of synkinematic clay minerals permit to determine the origin of the fluid from which they precipitated as well as the mechanisms of deformation. Our study is focused on clay mineral assemblages (illite and chlorite) in a major thrust fault located in the Monte Perdido massif (southern Pyrenees), a shallow thrust that affects upper cretaceous-paleocene platform carbonates and lower Eocene marls and turbidites. It implied 3?km of displacement of the Monte Perdido thrust unit with respect to the underlying Gavarnie unit. In this area the cleavage development by pressure-solution is linked to the Monte Perdido and Gavarnie thrust activity. The core zone of the fault, about 6?m thick, consists of an interval of intensely deformed clay-bearing rocks bounded by major shear surfaces. The deformed sediment is markedly darker than the protolith. Calcite-quartz shear veins along the shear planes are abundant. Detailed SEM and TEM observations of highly deformed fault zone samples indicate that clay mineral enrichment in the core zone of the fault is not only related to passive increase by pressure-solution mechanism but that dissolution?Crecrystallization of phyllosilicates occurs during deformation. A mineral segregation is observed in the highly deformed zone. Newly formed 2M 1 muscovite is present along the cleavage whereas IIb chlorite crystals fill SV2 shear veins suggesting syntectonic growth of phyllosilicates in the presence of fluids in low-grade metamorphic conditions. These mineralogical reactions act as weakening processes and would favour Monte Perdido fault creeping. 相似文献