Chaigneau Alexis, Dominguez N., Eldin Gérard, Vasquez L., Flores R., Grados C., Echevin Vincent. (2013). Near-coastal circulation in the Northern Humboldt Current System from shipboard ADCP data. Journal of Geophysical Research. Oceans, 118 (10), p. 5251-5266. ISSN 2169-9275.
Titre du document
Near-coastal circulation in the Northern Humboldt Current System from shipboard ADCP data
Chaigneau Alexis, Dominguez N., Eldin Gérard, Vasquez L., Flores R., Grados C., Echevin Vincent
Source
Journal of Geophysical Research. Oceans, 2013,
118 (10), p. 5251-5266 ISSN 2169-9275
The near-coastal circulation of the Northern Humboldt Current System is described analyzing approximate to 8700 velocity profiles acquired by a shipboard acoustic Doppler current profiler (SADCP) during 21 surveys realized between 2008 and 2012 along the Peruvian coast. This data set permits observation of (i) part of the Peru Coastal Current and the Peru Oceanic Current that flow equatorward in near-surface layers close to the coast and farther than approximate to 150 km from the coast, respectively; (ii) the Peru-Chile Undercurrent (PCUC) flowing poleward in subsurface layers along the outer continental shelf and inner slope; (iii) the near-surfacing Equatorial Undercurrent renamed as Ecuador-Peru Coastal Current that feeds the PCUC; and (iv) a deep equatorward current, referred to as the Chile-Peru Deep Coastal Current, flowing below the PCUC. A focus in the PCUC core layer shows that this current exhibits typical velocities of 5-10 cm s(-1). The PCUC deepens with an increasing thickness poleward, consistent with the alongshore conservation of potential vorticity. The PCUC mass transport increases from approximate to 1.8 Sv at 5 degrees S to a maximum value of approximate to 5.2 Sv at 15 degrees S, partly explained by the Sverdrup balance. The PCUC experiences relatively weak seasonal variability and the confluence of eddy-like structures and coastal currents strongly complicates the circulation. The PCUC intensity is also affected by the southward propagation of coastally trapped waves, as revealed by a strong PCUC intensification in March 2010 coincident with the passage of a downwelling coastal wave associated with a weak El Nino event.
