North Atlantic surface circulation during the 1990's observed with satellite-tracked drifters

摘要: A new compilation of Lagrangian velocity observations describes the state North Atlantic surface circulation during 1990s. Gridded fields and eddy kinetic energy (EKE) are constructed from trajectories more than 1500 15-m drogued satellite-tracked drifters in service between January 1990 December 1999. This time period overlaps a coordinated field study variability completed 1996–2000 as part World Ocean Circulation Experiment. We describe construction self-consistent drifter climatology, present decadal-mean quasi-Eulerian EKE computed on 1° grid, compare these results with contemporary satellite measurements. Detailed discussion inferred is focused three regions: (1) The Gulf Stream Current, (2) Labrador Sea subpolar gyre, (3) Caribbean Sea. swiftest motions were found equatorial region along tropical, subtropical, western boundaries. maximum instantaneous speed determined single (quality-controlled filtered) observation was 273 cm s−1 southeast Cape Cod. highest value (2790 cm2 s−2) just downstream New England Seamounts. Over most basin, drifter-derived values to be O(100 higher corresponding derived altimetry. In sharply elevated appears geographically related localized ejection (and by extension, mass energy) energetic West Greenland Current 60° 62°N. When compared measurements made late 1970s our suggest (but do not statistically confirm) an enhancement slight northward shift zonal extension. Such consistent sign expectations based observed interdecadal variations wind stress subtropical gyre potential associated Oscillation.