On the long‐term stability of Gulf Stream transport based on 20 years of direct measurements

Abstract

Abstract 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 −1 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.