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| Flament, P; Lepretre, A; Noel, S; Auger, Y. |
| Dix-huit prélèvements d'aérosols ont été effectués en Manche Nord, soit en bordure de mer, soit à quelques milles au large, à l'aide d'un impacteur à cascade (5 étages). L'ensemble des données (concentrations de 8 éléments répartis en 6 classes granulométriques successives) est exploité par analyse factorielle des correspondances. Celle-ci permet de mettre en évidence de larges déformations dans les spectres granulométriques pour les éléments traceurs marin et terrestre (Na et Al). En opposition, les métaux résultant d'activité anthropique (Fe, Pb, Zn, Mn), ont des comportements beaucoup plus typés. Parmi ceux-ci, la présence du manganèse sur le site paraît être indépendante de celle des autres métaux et imputable à une seule source. Pb, Fe, Zn et cuivre... |
| Tipo: Text |
Palavras-chave: Aérosols; Éléments-traces; Analyse par correspondance; Distribution granulométrique; Littoral; Aerosols; Trace elements; Correspondence analysis; Size distribution; Coastal. |
| Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/00110/22082/19723.pdf |
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| Chapalain, G; Smaoui, H; Lepretre, A; Nguyen, Kd; Ouahsine, A; Tessier, B. |
| The present paper deals with the modelling of hydro-sedimentary processes in the coastal area near Cape Gris-Nez and Cape Blanc-Nez (Dover Strait). The modelling procedure consists in coupling different hydro-sedimentary process models with a high spatial resolution two-dimensional tidal flow model (Nguyen and Ouahsine, 1992). The sediment transport models used include two semi-empirical models based on a dimensionless analysis and energetic concepts (Ackers and White, 1973; Engelund and Hansen, 1967), and a more heuristic cu (concentration times velocity) model (van Rijn, 1984 a; b). All these models are applied to predict instantaneous and tidally-integrated sediment transports in the area under investigation. |
| Tipo: Text |
Palavras-chave: DOVER STRAIT; TIDAL CURRENTS; COASTAL SEDIMENTS; HYDRO-SEDIMENTARY PROCESSES; MODELING. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00100/21140/18760.pdf |
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| Carpenter, P; Dewarumez, Jm; Lepretre, A. |
| The Abra alba community from the Gravelines area has been studied since 1976. During this period, sudden and unpredictable variations of the species composition have been observed. These important changes affect a limited number of species without changing the bionomical structure of the community. The species in question are found to be characteristic of this community, and are the more abundant ones. Multivariate statistical methods were used to study quantitative data on the benthic population collected from 1978 to 1992. This analysis was performed in association with air temperature data. Results showed the existence of a six- or seven-year cycle, and this is confirmed by the observation of two complete periods. This cycle, which is found to be... |
| Tipo: Text |
Palavras-chave: Long-term trends; Time series; Multivariate; Methods; Benthos. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20398/18065.pdf |
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