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Wind-induced exchange at the entrance to Concepción Bay, an equatorward facing embayment in central Chile

2004; Elsevier BV; Volume: 51; Issue: 20-21 Linguagem: Inglês

10.1016/j.dsr2.2004.08.010

1879-0100

Arnoldo Valle‐Levinson, Wolfgang Schneider, Marcus Sobarzo, Mónica Bello, Luis Bravo, Manuel Castillo, Luis Orlando Duarte, Rosalino Fuenzalida, J.M. Gallegos, José Garcés‐Vargas, Jean‐Louis Gonzalez, Dimitri Gutiérrez, Carlos Molinet, M.S. Navarro, Jorge O. Pierini, Efraín Rodríguez Rubio, Alexander Valdenegro, Leonor Vera, Lisette Zenteno,

Ocean Waves and Remote Sensing

Hydrographic and underway water velocity profiles were measured at the entrance to Concepción Bay, an equatorward facing embayment in central Chile, in order to illustrate the wind-induced exchange flow. Observations took place over a 25-h period (5–6 January 2002) during the austral summer, which is characterized by upwelling winds in the region. One portion of the observational transect was directly influenced by the wind and the other was protected from such influence by an island. The portion of the transect influenced by wind showed a surface layer, delimited by a pycnocline, moving downwind owing to the direct action of wind stress. This surface transport should have caused an onshore decrease of surface elevation that would drive upwind flow below the surface layer. The portion of the transect protected by the island was influenced by its wake and perhaps forced by a semidiurnal tide. This study is one of the few observational examples of wind-induced flow that documents the wind-induced exchange pattern under weak internal friction (low Ekman number). This pattern consists of downwind flow in an upper layer delimited by the pycnocline and upwind flow below.