HR: 1300h
AN: OS52D-04    [PDF]
TI: Near-surface Circulation in the Tropical Atlantic
AU: * Lumpkin, R
EM: Rick.Lumpkin@noaa.gov
AF: Cooperative Institute for Marine and Atmospheric Sciences, 4301 Rickenbacker Cswy, Miami, FL 33149-1097 United States
AU: Garzoli, S L
EM: Silvia.Garzoli@noaa.gov
AF: Atlantic Oceanographic and Meteorological Laboratory, 4301 Rickenbacker Cswy, Miami, FL 33149-1097 United States
AB: Satellite-tracked surface drifting buoy observations are examined in the tropical Atlantic Ocean, a region previously lacking enough of these observations to resolve many features of the circulation. Near-surface currents and sea surface temperatures are grouped into bins and simultaneously decomposed into time mean values, annual and semiannual harmonics, and an eddy residual with nonzero integral time scale. This analysis technique reduces biases in the means caused by inhomogeneous sampling of strong seasonal variability. Features of the time-mean circulation and its seasonal variations are resolved at unprecedented scales, for both total and Ekman-removed velocities. The drifter observations reveal the branches of the South Equatorial Current (SEC) which form or join with the North Brazil Current (NBC), correlated annual fluctuations in the strengths of the NBC retroflection, western North Equatorial Countercurrent (NECC) and SEC, and flow along the Guyana Coast, and strong semiannual variations in the equatorial band of the central basin. Conduits are traced which link seasonal variations of the equatorial current system's strength with the northern and southern hemisphere subtropical gyres. These findings update key results of the two decade old SEQUAL/FOCAL programs, and allow generation of a new monthly climatology of near-surface currents and concurrent SST in the tropical Atlantic Ocean.
DE: 1620 Climate dynamics (3309)
DE: 4231 Equatorial oceanography
DE: 4512 Currents
DE: 4572 Upper ocean processes
DE: 4576 Western boundary currents
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting