Malvinas-slope water intrusions on the northern Patagonia continental shelf

PIOLA, A. R.; MARTINEZ AVELLANEDA, N.; GUERRERO, R. A. ; JARDON, F. P.; PALMA, E. D.; ROMERO, S. I.

OCEAN SCIENCE (OS)

COPERNICUS PUBLICATIONS

Lugar: Gottingen; Año: 2010 vol. 6 p. 345 - 359

1812-0784

The Patagonia continental shelf located off southeasternSouth America is bounded offshore by the MalvinasCurrent, which extends northward from northern Drake Passage(55 S) to nearly 38 S. The transition between relativelywarm-fresh shelf waters and Subantarctic Waters fromthe western boundary current is characterized by a thermohalinefront extending nearly 2500 km. We use satellite derivedsea surface temperature, and chlorophyll-a data combinedwith hydrographic and surface drifter data to documentthe intrusions of slope waters onto the continental shelf near41 S. These intrusions create vertically coherent localizednegative temperature and positive salinity anomalies extendingonshore about 150 km from the shelf break. The regionis associated with a center of action of the first mode of nonseasonalsea surface temperature variability and also relativelyhigh chlorophyll-a variability, suggesting that the intrusionsare important in promoting the local development ofphytoplankton. The generation of slope water penetrations atthis location may be triggered by the inshore excursion of the100m isobath, which appears to steer the Malvinas Currentwaters over the outer shelf.