Data/hora: 16/06/2024 08:44:14

Provedor de dados: | 5
País: | France
Título: | Dynamique des matières en suspensions minérales des eaux de surface de la Manche observée par satellite et modélisée numériquement.
Autores: | Rivier, Aurelie.
Data: | 2013-07-04
Ano: | 2013
Palavras-chave: | Matière en suspension; Télédétection; Satellite; Modélisation; Manche; Sédiments; Turbidité; Marée; Houle; Suspended particulate matter; Satellite; Remote-sensing; Modelling; English Channel; Sediments; Turbidity; Tide; Wave.
Resumo: | Study of mineral suspended particulate matter (SPM) is essential to understand ecosystem dynamics. SPM influences light penetration which is closely related to primary production and carries pollutants and nutrients within the water masses. This work aims to study near-surface mineral SPM dynamics in the English Channel using two complementary methods: remote-sensing by satellites and numerical modelling. Firstly, MODIS and MERIS satellite images processed by the IFREMER semi-analytical algorithm and describing non-algal SPM, are analysed to build three statistical models which are able to estimate near-surface SPM using simple variables, e.g., tidal coefficient, significant wave height and mean chlorophyll-a concentration. Secondly, the three-dimensional hydrosedimentary model ROMS (Regional Ocean Modeling System) is applied in the English Channel. It considers tidal forcing along open boundaries, wind stress at the sea-surface, wave-current interactions in the bottom boundary layer and realistic heterogeneous bottom sediments. Results of the more sophisticated statistical model is also used to impose SPM concentrations at open boundaries. Sensitivity tests on SPM boundary conditions show the importance of prescribing realistic sediment concentrations to improve the model predictions. Biological influences on mineral SPM are also tested using settling velocity and critical shear stress for erosion which vary with seasons. Both statistical and numerical models highlight and locate respective influences of tide, waves and biology on mineral SPM. Numerical predictions indicate that near-surface SPM is mainly composed of silts (&gt;70%). Near-surface suspended silts come largely from seabed resuspension alongshore in the Eastern Channel and from the open boundaries of our limited-area coastal model at the West of Cotentin Peninsula and offshore. Near-surface SPM variations are investigated at semi-diurnal, neap-spring tidal cycle time scales and during a wave event. Finally, dynamics of sediments in the turbidity maximum zone around the Isle of Wight is examined depending on hydrodynamical conditions in order to distinguish the role played by advection and local erosion/settling processes in this area.  Keywords: Suspended particulate matter, satellite, remote-sensing, modelling, English Channel, sediments, turbidity, tide, wave
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/00157/26783/24884.pdf
Editor: | Université de Bretagne Occidentale
Relação: | http://archimer.ifremer.fr/doc/00157/26783/
Formato: | application/pdf
Fonte: | 2013 UBO