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Abstract

Weekly to monthly regional mean sea-level fluctuations on the shelf northwest of Europe reach several tens of centimetres from peak to peak. They feature at the coast and are non-negligible component of extreme coastal sea levels in Europe, despite their subinertial periodicity and broad spatial scale. A greater understanding of their spatio-temporal scales and their drivers is critical to the understanding of extreme sea levels at the O(10cm) scale. In particular, the common mode of European mean sea level, which explains a substantial fraction of the weekly mean sea-level variability, has been hypothesized to reflect the strength of the European slope current (Chafik et al., 2017). This circulation is a wind and density driven quasi-barotropic circulation (Huthnance et al., 2020). We present substantial evidence based on in-situ current measurements that, indeed, European sea levels covary with along-isobath currents, although above shallower depths (150-400m m of water depth) relative to where the density-driven slope current is believed to flow. We discuss how these elevated (or depressed) sea levels can be driven and maintained through the joint effect of winds and bathymetry. Chafik, L., Nilsen, J. E. Ø., & Dangendorf, S. (2017). Impact of North Atlantic teleconnection patterns on Northern European sea level. Journal of Marine Science and Engineering, 5(3), 43. Huthnance, J. M., Inall, M. E., & Fraser, N. J. (2020). Oceanic density/pressure gradients and slope currents. Journal of Physical Oceanography, 50(6), 1643-1654.