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[1] Since 1992, upper ocean ADCP current data between New York and Bermuda have been gathered from the container ship Oleander to identify long-term changes in the shelf, slope, Gulf Stream and Sargasso Sea. Temperature and surface salinity data have been been collected along this route since 1978 by NOAA/NMFRC. The first ten years of ADCP data from which the effects of warm ring have been removed are used to describe processes within the shelfbreak frontal sub-region. The Eulerian mean velocity structure shows an along-isobath shelfbreak jet with maximum speeds of O(0.15 m s À1 ) offshore of which is a $30 km wide relatively quiescent region. There is also an offshore slope current 40 to 50 km wide extending vertically to 300 m, with similar velocities as those found in the shelfbreak jet. The mean shelfbreak jet transport is 0.4 Sv while the slope current adds another 2.5 Sv. Maximum shelfbreak transport occurs in the fall and winter while the slope current reaches its maximum during the spring. In stream coordinates, the shelfbreak jet has maximum speeds of 0.35 m s À1, a width of $30 km and a vertical decay scale of $50 m. The maximum Rossby number within the jet, defined by jdU/dyj max /f, is about 0.2. Significant interannual fluctuations occur in upper ocean temperature, salinity and currents, some of which appear related to changes in the NAO index. Seasonal changes in the slope current appear to be related to seasonal changes in the wind stress curl over the slope sea.

The wavenumber spectra for velocity and temperature in the Gulf Stream region are calculated from a decade (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004) of shipboard acoustic Doppler current profiler (ADCP) measurements taken as part of the Oleander Project. The velocity and temperature spectra have comparable magnitude, in terms of the kinetic and potential energy, and both indicate a k -3 slope. These results are in agreement with twodimensional quasigeostrophic turbulence theory. In contrast, velocity spectrum determined from satellite altimetry sea surface height yields a significantly higher energy and a k -2 slope. This discrepancy between directly-measured and altimeter-derived velocity spectra suggests a noise contribution to altimetry along-track sea surface height data. These results also highlight large gaps in the current understanding of the nature of surface geostrophic turbulence.3

In contrast to recent claims of a Gulf Stream slowdown, two decades of directly measured velocity across the current show no evidence of a decrease. Using a well-constrained definition of Gulf Stream width, the linear least square fit yields a mean surface layer transport of 1.35 × 10 5 m 2 s À1 with a 0.13%negative trend per year. Assuming geostrophy, this corresponds to a mean cross-stream sea level difference of 1.17 m, with sea level decreasing 0.03 m over the 20 year period. This is not significant at the 95% confidence level, and it is a factor of 2-4 less than that alleged from accelerated sea level rise along the U.S. Coast north of Cape Hatteras. Part of the disparity can be traced to the spatial complexity of altimetric sea level trends over the same period.

Determining the exchange of water across the Iceland‐Faroe‐Scotland ridge is of fundamental interest because it measures the rate of transformation of North Atlantic water into dense water and thus the strength of the meridional overturning circulation (MOC). Here we study this exchange by monitoring all water flowing through the area east of Iceland to near the bottom or ∼600 m depth using a 75 kHz acoustic Doppler current profiler (ADCP) mounted on the high‐seas ferry M/F Norröna. Starting in March 2008, currents have been measured in the Faroe‐Shetland Channel (FSC) and along the Iceland‐Faroe Ridge (IFR) on the ferry's weekly round‐trips between Iceland and Denmark. The detided average transports (to the north) across the two sections are 4.1 ± 0.1 Sv (106 m2s−1) through the FSC and 4.4 ± 0.25 Sv across the IFR (this excludes ∼1.6 Sv circulating around the Faroes). The Norröna program is ongoing.