Feb 6, 2013

Gulf Stream's induced sea level rise and variability along the U.S. mid‐Atlantic coast

Ezer, Tal, Atkinson, Larry P., Corlett, William B., Blanco, Jose L.
Journal of Geophysical Research: Oceans
  • States that recent studies indicate the rates of sea level rise (SLR) along the U.S. mid-Atlantic coast have accelerated in recent decades, possibly due to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC) and its upper branch, the Gulf Stream (GS)
  • Analyzes the GS elevation gradient obtained from altimeter data, the Florida Current transport obtained from cable measurements, the North Atlantic Oscillation (NAO) index, and coastal sea level obtained from 10 tide gauge stations in the Chesapeake Bay and the mid-Atlantic coast
  • Uses an Empirical Mode Decomposition/Hilbert-Huang Transformation (EMD/HHT) method to separate long-term trends from oscillating modes
  • Finds that the coastal sea level variations were strongly influenced by variations in the GS on timescales ranging from a few months to decades
  • Finds the GS has shifted from a 6–8 year oscillation cycle to a continuous weakening trend since about 2004 and that this trend may be responsible for recent acceleration in local SLR
  • Finds the correlation between long-term changes in the coastal sea level and changes in the GS strength was extremely high (R = −0.85 with more than 99.99% confidence that the correlation is not zero)
  • Finds the impact of the GS on SLR rates over the past decade seems to be larger in the southern portion of the mid-Atlantic Bight near Cape Hatteras and is reduced northward along the coast
  • Concludes by suggesting that regional coastal sea level rise projections due to climate change must take into account the impact of spatial changes in ocean dynamics