Assessment of Tidal Range Changes in the North Sea From 1958 to 2014

Abstract

For thousands of years, tides have had a great influence on coastal areas globally and their residents. Today they play a critical role in influencing economic considerations, nautical safety, renewable energy schemes, assessments of land erosion, and the definition of geodetic datums (Haigh et al., 2020; Pugh & Woodworth, 2014). Tides not only control the navigability of some ports and sea routes, but also have a major influence on the intensity and timing of extreme sea levels during storm surges (e.g., Arns et al., 2020; Horsburgh & Wilson, 2007; Prandle & Wolf, 1978). Given their close connection to the periodic and predictable nature of astronomical variations, the amplitudes and phases of tidal constituents, and corresponding tidal water levels, are generally assumed to be constant on time scales over which basin geometry undergoes only minor changes (i.e., decades to centuries). However, Keller (1901) showed increased tidal amplitudes due to reflection and local resonance changes as a result of building measures such as weirs (e.g., in the Ems River). Similarly Doodson (1924) pointed to appreciable secular perturbations in the local tidal regimes of

Predominant landward skewing of tidal meanders

“…Tidal regimes of individual study cases were also differentiated based on the values of tidal ranges. The latter were computed using tidal-gauge water level data from Dong (2020), with tidal ranges being classified as macro-tidal when >4 m, meso-tidal from 2-4 m, and microtidal if <2 m (Jänicke et al, 2021). Tidal asymmetry can be determined directly by two methods according to its definition: duration asymmetry, according to which flood-dominant currents have a ratio between ebb duration and flood duration ρ d > 1; and velocity asymmetry, according to which flood-dominant currents have a ratio between peak-flood velocity and peak-ebb velocity ρ v > 1.…”

Mean Sea Level and Tidal Change in Ireland since 1842: A case study of Cork

“…Woodworth (2010) showed mixed trends in M2 amplitude around Britain, with decreasing phase of M2 to the south along the west coast of Britain. The global presence of small, usually local, changes of tides is comprehensively reviewed in (Haigh et al 2020) and for a recent discussion for the North Sea area, see (Jänicke et al 2021). The stability of Cork Harbour tides is not uncommon, despite some local dredging and land recovery.…”

“…Sea level is a combination of mean sea level (MSL), tide, and a non-tidal residual due to weather and other causes (Pugh and Woodworth 2014). Mean sea levels are rising globally as a consequence of anthropogenic climate change (Stocker et al 2013) and tides are also changing in some local areas (Haigh et al 2020;Jänicke et al 2021), due to coastal changes, and potentially due to rising sea levels (Idier et al 2017). Knowledge of regional changes in mean sea level from global trends, and changes in tides are crucial to inform effective local climate adaptation (Talke et al 2018).…”

Seascape genomics identify adaptive barriers correlated to tidal amplitude in the shore crabCarcinus maenas

“…Acronyms are as follows: O, Odense; V, Varberg; K, Kristineberg; T, Tyboron; I, Hvide Sand; E, Esbjerg; S, Sylt; H, Hooksiel; X, Texel; Y, Yerseke; D, Dunkirk; B, Bangor. Red lines indicate distinctions between micro‐ (<2 m) in the Skagerrak and Kattegat, meso‐ (2–4 m) in the Wadden sea and macrotidal (>4 m) in the English channel according to Jänicke et al (2020). Red dotted lines indicate “adaptive barriers” as identified in Figure 4.…”