Articles | Volume 6, issue 1
Ocean Sci., 6, 345–359, 2010

Special issue: Deep ocean exchange with the shelf

Ocean Sci., 6, 345–359, 2010

  08 Mar 2010

08 Mar 2010

Malvinas-slope water intrusions on the northern Patagonia continental shelf

A. R. Piola1,2, N. Martínez Avellaneda3, R. A. Guerrero4, F. P. Jardón5, E. D. Palma6,7, and S. I. Romero1,2 A. R. Piola et al.
  • 1Departamento Oceanografía, Servicio de Hidrografía Naval, Buenos Aires, Argentina
  • 2Departamento de Ciencias de la Atmósfera y los Océanos, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
  • 3Institut für Meereskunde, KlimaCampus, Universität Hamburg, Hamburg, Germany
  • 4Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Argentina
  • 5Laboratoire d'Océanographie et du Climat, Université de Paris VI, Paris, France
  • 6Departamento de Física, Universidad Nacional del Sur, Bahía Blanca, Argentina
  • 7Instituto Argentino de Oceanografía, CONICET, Bahía Blanca, Argentina

Abstract. The Patagonia continental shelf located off southeastern South America is bounded offshore by the Malvinas Current, which extends northward from northern Drake Passage (~55° S) to nearly 38° S. The transition between relatively warm-fresh shelf waters and Subantarctic Waters from the western boundary current is characterized by a thermohaline front extending nearly 2500 km. We use satellite derived sea surface temperature, and chlorophyll-a data combined with hydrographic and surface drifter data to document the intrusions of slope waters onto the continental shelf near 41° S. These intrusions create vertically coherent localized negative temperature and positive salinity anomalies extending onshore about 150 km from the shelf break. The region is associated with a center of action of the first mode of non-seasonal sea surface temperature variability and also relatively high chlorophyll-a variability, suggesting that the intrusions are important in promoting the local development of phytoplankton. The generation of slope water penetrations at this location may be triggered by the inshore excursion of the 100 m isobath, which appears to steer the Malvinas Current waters over the outer shelf.