부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecss.2005.06.016 Byline: A. PiA[+ or -]ones (a)(b), A. Valle-Levinson (b), D.A. Narvaez (a)(b), C.A. Vargas (c), S.A. Navarrete (a), G. Yuras (d), J.C. Castilla (a) Abstract: Time series and shipboard observations of hydrography and current velocity were used to describe the motion of the Maipo River plume, in central Chile, and its influence on inner shelf hydrographic conditions. Observations showed fundamental seasonal changes in the forcing of the plume as recorded by hourly coastal salinities at a location 12km upstream (in the Kelvin wave sense) of the river mouth. During austral fall-winter, synoptic-scale rainfall pulses modulated river discharge and coastal salinity variations. In contrast, during spring-summer river discharge changed little, but coastal salinity showed a clear diurnal cycle associated with sea breezes. The lowest coastal salinity was observed with daily regularity, between 17:00 and 22:00 hours (local time), at the end of the onshore phase of the sea breeze. Salinity increased as the breeze relaxed or reversed direction. Spatial variability of the plume, as determined from shipboard surveys, indicated that low salinities were persistently shallower than 10m during spring-summer. The thickness of the Maipo River plume characterized it as "surface-advected", which allowed a relatively rapid response to diurnal variations in wind stress. During autumn-winter, the earth's rotation may influence the spatial distribution of the plume in the absence of strong onshore wind, as observed from shipboard measurements and satellite images. This constitutes one of the few studies to date that document diurnal switching of a river plume caused by wind forcing and the consequences of such diurnal switching on inner shelf hydrography. Author Affiliation: (a) Estacion Costera de Investigaciones Marinas y Centro de Estudios Avanzados en Ecologia y Biodiversidad, Pontificia Universidad Catolica de Chile, Casilla 114-D, Santiago 6513677, Chile (b) Center for Coastal Physical Oceanography, Department of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Crittenton Hall, 768 West 52nd Street, Norfolk, VA 23529, USA (c) Departamento de Oceanografia, Estacion de Biologia Marina Dichato, Universidad de Concepcion, P.O. Box 160-C, Concepcion, Chile (d) Programa Regional de Oceanografia Fisica y Clima, Universidad de Concepcion, Cabina 7, Barrio Universitario s/n, Concepcion, Chile Article History: Received 23 August 2004; Accepted 29 June 2005