Nonlinear Sea-Level Trends and Long-Term Variability on Western European Coasts

• Published in: Journal of Coastal Research
• Main Authors: Ezer, Tal, Haigh, I. D., Woodworth, P. L.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: ODU Digital Commons 2015
• Subjects: Sea Level; European Coasts; Oceanography and Atmospheric Sciences and Meteorology; Labrador Sea; North Atlantic; North Atlantic oscillation
• Online Access: https://digitalcommons.odu.edu/ccpo_pubs/152; https://doi.org/10.2112/JCOASTRES-D-15-00165.1; http://www.jcronline.org/doi/abs/10.2112/JCOASTRES-D-15-00165.1

Nonlinear trends and long-term variability in sea level measured on the U.K. and western European coasts with long tide-gauge records (~100–200 y) were investigated. Two different analysis methods, a standard quadratic regression and a nonparametric, empirical mode decomposition method, detected similar positive sea-level accelerations during the past ~150 years: 0.014 ± 0.003 and 0.012 ± 0.004 mm/y2, respectively; these values are close to the sea-level acceleration of the global ocean over the same period, as reported by several studies. Ensemble calculations with added white noise are used to evaluate the robustness of low-frequency oscillations and to estimate potential errors. Sensitivity experiments evaluate the impact of data gaps on the ability of the analysis to detect decadal variations and acceleration in sea level. The long-term oscillations have typical periods of 15–60 years and ranges of 50–80 mm; these oscillations appear to be influenced by the North Atlantic Oscillation and by the Atlantic Multidecadal Oscillation. Analysis of altimeter data over the entire North Atlantic Ocean shows that the highest impact of the North Atlantic Oscillation is on sea-level variability in the North Sea and the Norwegian coasts, whereas the Atlantic Multidecadal Oscillation has the largest correlation with sea level in the subpolar gyre and the Labrador Sea, west of the study area.