South Atlantic Large-scale Variability and its Relation with the SAMOC

ELBIO D. PALMA; RICARDO P. MATANO

Portland

Congreso; https://osm.agu.org/2018/scientific-program-overview/; 2018

American Geophysical Union

We use results of the Simple Ocean Data Assimilation Model to describe the dominant patterns of large-scale, lowfrequency variability of the South Atlantic circulation and their impact on the South Atlantic branch of the Atlantic Meridional Overturning Circulation (SAMOC). EOF analysis identify three distinct variability modes: a subtropical mode, a mode representing the equatorial/eastern Atlantic connection and a mode representing the variability of the circulation in the western portion of the tropical Atlantic. The time series of these modes show significant spectral peaks at ENSO and quasi-biannual time scales. The first and second modes are the most closely related to the variability of the SAMOC. A decomposition of the SAMOC into geostrophic shear, Ekman, and external modecomponents shows that the geostrophic shear is dominant at all latitudes.