Search results for "Spatiale"
showing 10 items of 197 documents
Fractals and geography
2007
Bayesian spatio-temporal approach to identifying fish nurseries by validating persistence areas
2015
Spatial and temporal closures of fish nursery areas to fishing have recently been recognized as useful tools for efficient fisheries management, as they preserve the reproductive potential of populations and increase the recruitment of target species. In order to identify and locate potential nursery areas for spatio-temporal closures, a solid understanding of species− environment relationships is needed, as well as spatial identification of fish nurseries through the application of robust analyses. One way to achieve knowledge of fish nurseries is to analyse the persistence of recruitment hotspots. In this study, we propose the comparison of different spatiotemporal model structures to ass…
Fishery-dependent and -independent data lead to consistent estimations of essential habitats
2016
AbstractSpecies mapping is an essential tool for conservation programmes as it provides clear pictures of the distribution of marine resources. However, in fishery ecology, the amount of objective scientific information is limited and data may not always be directly comparable. Information about the distribution of marine species can be derived from two main sources: fishery-independent data (scientific surveys at sea) and fishery-dependent data (collection and sampling by observers in commercial vessels). The aim of this paper is to compare whether these two different sources produce similar, complementary, or different results. We compare them in the specific context of identifying the Es…
Microbiology and atmospheric processes: research challenges concerning the impact of airborne micro-organisms on the atmosphere and climate
2011
Cet article a fait l'objet d'une discussion dans "Morris, C. E., Sands, D. C., Bardin, M., Jaenicke, R., Vogel, B., Leyronas, C., Ariya, P. A., and Psenner, R.: Microbiology and atmospheric processes: an upcoming era of research on bio-meteorology, Biogeosciences Discuss., 5, 191-212, doi:10.5194/bgd-5-191-2008, 2008."; International audience; For the past 200 years, the field of aerobiology has explored the abundance, diversity, survival and transport of micro-organisms in the atmosphere. Micro-organisms have been explored as passive and severely stressed riders of atmospheric transport systems. Recently, an interest in the active roles of these micro-organisms has emerged along with prop…
GEOV1: LAI, FAPAR essential climate variables and FCOVER global time series capitalizing over existing products. Part 2: Validation and intercomparis…
2013
International audience; This paper describes the scientific validation of the first version of global biophysical products (i.e., leaf area index, fraction of absorbed photosynthetically active radiation and fraction of vegetation cover), namely GEOV1, developed in the framework of the geoland-2/BioPar core mapping service at 1 km spatial resolution and 10-days temporal frequency. The strategy follows the recommendations of the CEOS/WGCV Land Product Validation for LAI global products validation. Several criteria of performance were evaluated, including continuity, spatial and temporal consistency, dynamic range of retrievals, statistical analysis per biome type, precision and accuracy. The…
Montagnes d’Afrique tropicale : marqueurs de la variabilité climatique ou isolats climatiques ?
2011
6 pages; International audience; Les montagnes tropicales sont souvent perçues comme des sentinelles des changements climatiques. Pour autantles variations climatiques interannuelles à décennales sont-elles le reflet de celles des espaces environnants ? A l’échelle del’Afrique au sud du Sahara, une analyse de la variabilité des pluies entre 1941 et 2000 montre une cohérence spatiale peudiminuée par les reliefs. Des exemples sont présentés de reliefs constituant même des révélateurs de la dynamiqueatmosphérique et de la variabilité climatique d’échelles larges.
Centres secondaires et recomposition économique des espaces urbains
2002
The object of this paper is to analyze the multicentric features of the Agglomeration of Dijon by studying the spatial organization of the economic activities and population. The study relates to the territory of the Agglomeration Community of Dijon (COMADI), which is composed of 16 towns. The space scale used is Iris-2000 zoning for the communes of more than 5000 inhabitants and the communal scale for the other towns belonging to the COMADI: the sample includes 114 observations. We use two databases available for two years (1990 and 1999): the SIRENE data for the employment by sectors of activities (ACTET10 and NAF700nomenclatures) and the data of the RGP for the population. We study the s…
Penser la ville durable : positionner la modélisation et l’évaluation des territoires dans les processus d’aménagement
2015
National audience; Les politiques d’aménagement du territoire sont guidées depuis deux décennies par les objectifs du développement durable. Én¬oncé dans le rapport de G.H. Brundtland (1987) réalisé pour le compte des Nations-Unies, l’expression « développement du¬rable » définit en effet un « développe¬ment qui répond au besoin du présent sans compromettre la capacité des généra¬tions futures à satisfaire leurs propres be¬soins ». Trois sphères distinctes mais qui se chevauchent sont identifiées, dans les¬quelles les principes de développement du¬rable doivent être appliqués : l’économique, le social et l’environnemental, la combi¬naison des trois faisant théoriquement at¬teindre le niveau…
Lire les lignes de la Ville
2017
National audience; La ville est un système très riche qui regroupe une multitude d’éléments en interactions les uns avec les autres. Elle peut être lue de diverses manières, et, selon le regard porté, révéler ses qualités politiques, culturelles, sociales... L’angle de vue que nous avons choisi pour ce travail est celui morphologique.
Microlensing Discovery of a Population of Very Tight, Very Low Mass Binary Brown Dwarfs
2013
Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M [SUB]⊙[/SUB] and 0.034 M [SUB]⊙[/SUB], and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can …