Long-Term Wind Influence on Sea-Level Change Along the Dutch Coast

Abstract

The sea level along the Dutch coast contains a robust interannual variability, of which a substantial part is due to wind forcing. Correcting sea level observations for the wind influence helps to improve estimates of long-term rates of sea-level rise. We study the wind influence on multi-decadal sea-level variability and trend along the Dutch coast using three physically-based, multi-linear regression models. These models relate sea level and wind forcing either using zonal and meridional wind speeds or large-scale pressure patterns. We use annual mean sea level observations from six tide gauge stations spread along the Dutch coast covering 1890 to 2020, and surface wind and pressure data from the ERA5 and the Twentieth Century Reanalysis data sets, covering 1950 to 2020 and 1836 to 2015, respectively. The results from the regression analysis show a robust multi-decadal variability of wind influence on sea-level change with an amplitude of around 1 cm and a period of 40 to 60 years. This multi-decadal mode of variability is responsible for an average drop in sea level of 0.5 mm/yr over the last 40 years. Furthermore, it is shown that the multi-decadal wind variability is related to the Atlantic Multidecadal Variability (AMV). A regression analysis relating the low-frequency variability and AMV from 1950 to 2015 shows that the AMV explains a large part of the wind variability. Finally, the three regression models are applied to Coupled Model Intercomparison Project 6 (CMIP6) historical and future climate scenario data to make projections of the wind impact on sea-level change along the Dutch coast for the 21st century. We do not find significant effects of wind on sea-level rise for the Dutch coast during the 21st century, which contrasts earlier findings for the German Bight.