For the convenience of the readers, our basic results are shown in Figure 1. We identified five individual oscillations (upper panel), including a sea-level amplitude of 70 mm (top–bottom [t-b]) of the 18.6-year oscillation caused by the lunar nodal oscillation (LNO), whereas Schmith, Thejll, and Nielsen, with their method, found other spectra and found that the amplitude effect of the LNO would be only on the order of 10 mm (t-b) (i.e. one-seventh of what we found). These differences are neither strange nor inexplicable but are caused by the two fundamentally different methods (see section below).
Together with a general sea-level rise of 1.18 mm/y, the sum of these five sea-level oscillations constitutes a reconstructed or theoretical sea-level curve of the eastern North Sea to the central Baltic Sea (Figure 1, lower panel), which correlates very well with the observed sea-level changes of the 160-year...