| Popis: |
We studied the wind influence on multidecadal variability and trend of sea level along the Dutch coast. Annual mean sea level for the period 1890 to 2020 is obtained from 6 tide gauges. We compared three widely used multi-linear regression models relating sea level and wind based on either local zonal and meridional wind speed or large-scale pressure patterns. For this purpose, surface wind and pressure data from the ERA5 reanalysis and the twentieth century reanalysis v3 (20CRv3) are used. We find a significant multi-decadal mode of variability with an amplitude of around 1 cm and a period of 40 to 60 years that is related to the Atlantic Multidecadal Variability. We show that this multi-decadal wind variability is responsible for an average drop in sea level of 0.5 mm/yr over the last 40 years which is around a quarter of the total sea level rise of 2 mm/yr over that period. Therefore, wind effects on sea level partly masked sea level acceleration at the Dutch coast. This is important for sea level monitoring supporting decision making. The same multi-linear regression models are then applied to the CMIP6 historical and future climate scenario data to make projections of future wind impact on sea level along the Dutch coast. Contrary to our expectation based on a previous study in the German Bight (Dangendorf et al. 2014) we find no sign that long term wind changes will increase sea level during the 21st century. Reference: Dangendorf, Sönke, Thomas Wahl, Enno Nilson, Birgit Klein, and Jürgen Jensen. “A New Atmospheric Proxy for Sea Level Variability in the Southeastern North Sea: Observations and Future Ensemble Projections.” Climate Dynamics 43, no. 1–2 (July 2014): 447–67. https://doi.org/10.1007/s00382-013-1932-4. |
