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TitreIntratidal and neap-spring variations of suspended sediment concentrations and sediment transport processes in the North Branch of Changjiang Estuary
AuteurLi, Z; Li, M Z; Dai, Z; Zhao, F; Li, J
SourceActa Oceanologica Sinica vol. 34, no. 1, 2015 p. 137-147, https://doi.org/10.1007/s13131-015-0605-z
Année2015
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120400
ÉditeurSpringer
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1007/s13131-015-0605-z
Mediapapier; en ligne; numérique
Formatspdf
Lat/Long OENS 121.0000 122.5000 32.0000 31.0000
Sujetseaux de surface; rivières; estuaires; océanographie; transport des sediments; sediments en suspension; courants de marée; marées; charge en suspension; configurations lit; milieu sédimentaire; hydrogéologie; géologie marine
Illustrationslocation maps; time series; bar graphs; plots; profiles
ProgrammeÉnergies renouvelables, Géosciences de l'environnement
Résumé(disponible en anglais seulement)
Profiles of tidal current and suspended sediment concentration (SSC) were measured in the North Branch of the Changjiang Estuary from neap tide to spring tide in April 2010. The measurement data were analyzed to determine the characteristics of intratidal and neap-spring variations of SSC and suspended sediment transport. Modulated by tidal range and current speed, the tidal mean SSC increased from 0.5 kg/m3 in neap tide to 3.5 kg/m3 in spring tide. The intratidal variation of the depth-mean SSC can be summarized into three types: V-shape variation in neap tide, M-shape and mixed M-V shape variation in medium and spring tides. The occurrence of these variation types is controlled by the relative intensity and interaction of resuspension, settling and impact of water exchange from the rise and fall of tide. In neap tide the V-shape variation is mainly due to the dominant effect of the water exchange from the rise and fall of tide. During medium and spring tides, resuspension and settling processes become dominant. The interactions of these processes, together with the sustained high ebb current and shorter duration of low-tide slack, are responsible for the M-shape and M-V shape SSC variation. Weakly consolidated mud and high current speed cause significant resuspension and remarkable flood and ebb SSC peaks. Settling occurs at the slack water periods to cause SSC troughs and formation of a thin fluff layer on the bed. Fluxes of water and suspended sediment averaged over the neap-spring cycle are all seawards, but the magnitude and direction of tidal net sediment flux is highly variable.
GEOSCAN ID292226