Vertical structure of the Brazil Current

Abstract

Recent interest in world climate and interaction of the ocean and atmosphere have led to studies of the meridional fluxes of fresh water and heat in the ocean^1,2. Several such studies^3,4 have noted the asymmetry of heat fluxes between the North and South Atlantic oceans. In particular, the fluxes across both 24° N and 24° S appear to be northward. Crucial to all of the direct calculation techniques is an accurate estimate of the transport of the western boundary currents. In the North Atlantic, useful measurements in the Florida Current⁵ over a long period of time are available. For the much less studied South Atlantic no comparable time series has been made. The direct measurements of Brazil Current velocities near 23° S reported here show southward flow of warm water above 400 m depth and northward flow of Antarctic Intermediate Water below that. The upper layer transport was ∼6 × 10⁶ m³ s⁻¹ towards the south offshore of the 200-m isobath, with an indication of comparable flow on the shelf.