The rate of coastal sea level change in the northeast Pacific (NEP) has decreased in recent decades. The relative contributions to the decreased rate from remote equatorial wind stress, local longshore wind stress, and local windstress curl are examined. Regressions of sea level onto wind stress time series and comparisons be- tween NEP and Fremantle sea levels suggest that the decreased rate in the NEP is primarily due to oceanic adjustment to strengthened trade winds along the equatorial and coastal waveguides. When taking care to account for correlations between the various wind stress time series, the roles of longshore wind stress and local windstress curl are found to be of minor importance in comparison to equatorial forcing. The predictability of decadal sea level change rates along the NEP coastline is therefore largely determined by tropical variability. In addition, the importance of accounting for regional, wind-driven sea level variations when attempting to cal- culate accelerations in the long-term rate of sea level rise is demonstrated.

Figure. (right) Location of tide stations for (left),(middle) panels. (left) The fraction of sea level variance accounted for by the equatorial (yellow), longshore (blue), WSC (gray), and combined (red) components in a multiple regression. (middle) Linear rates of change during the altimeter period for the measured sea levels (black bar) and estimates of each contribution to the rate from the individual wind-forced components. Bars in this figure represent values for the orthogonalization when covariance between τ_ls and τ_xy is removed from τ_xy. The black circles represent the case when the covariance is removed from τ_ls.

Thompson, P. R., Merrifield, M. A., Wells, J. R., & Chang, C. M. (2014). Wind-driven coastal sea level variability in the Northeast Pacific. Journal of Climate, 27, 4733–4751. http://doi.org/10.1175/JCLI-D-13-00225.1

http://journals.ametsoc.org/doi/full/10.1175/JCLI-D-13-00225.1