Pathways of the North Atlantic Current from surface drifters and subsurface floats

The North Atlantic east of the Grand Banks presents a thermal front from 40 degrees to 50 degreesN between the warm North Atlantic Current (NAC) and t he cold Labrador Current. Here we use the trajectories of 84 isopycnal RAFO S floats deployed on the 27.2 and 27.5 sigma (T) surface in 1993-1995 and 2 18 surface drifters deployed by the International Ice Patrol and the Instit ut fur Meereskunde (Kiel, Germany) between 1978 and 1993 to understand the pathways of the NAG. The mean flow pattern, kinetic energy, directional sta bility, and most probable path through 1 degrees by 1 degrees boxes are der ived for each of the three surfaces. Speed and kinetic energy decrease with depth, although directional stability is comparable at all levels. The axi s of the NAG, which follows the 4000 m isobath along the western boundary, is described by mean kinetic energy (MKE) Values surpassing 100 cm(2) s(-2) on the float surfaces and correspond to regions with directional stabiliti es in excess of 60%. Maximum values of eddy kinetic energy are found just o ffshore of the maximum MKE associated with the NAC main pathway and decreas e rapidly to the east. Two cyclonic meanders are identified at 44 degreesN, 45 degreesW near the Newfoundland Seamounts and at 46 degreesN, 42 degrees W near Flemish Cap. The main difference between the patterns derived for th e surface drifters and floats was the greater eastward extent of the cyclon ic trough st 44 degreesN and intensity of the Mann Eddy (42 degreesN, 44 de greesW) during the float sampling period (1993-1995).