Egersund
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Egersund is a town in Eigersund Municipality in Rogaland county, Norway. The town is located along the southwestern coast of Norway, about 75 kilometres south of the city of Stavanger. The town is sit
View of the town
Present-day Egersund Church
Amphidromic point
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An amphidromic point, also called a tidal node, is a geographical location where there is little or no difference in sea height between high tide and low tide; it has zero tidal amplitude for one harm
Egersund
…surpassed by Ålesund in 2006). The tidal range, the difference in height between high tide and low tide, is practically zero due to the presence of an amphidromic point. Several internationally known companies have divisions here, like Navico (earlier Robertson autopilots) and Jeppesen Norway formerly C-MAP Norway…
Figure 1. The M2 tidal constituent, the amplitude indicated by color. The white lines are cotidal lines spaced at phase intervals of 30° (a bit over 1 hr). The amphidromic points are the dark blue areas where the lines come together.
Figure 2. Resonance between an incident and reflected wave and the resulting total wave. At certain points (nodes), the amplitude of the incident wave and the reflected wave cancel each other out. At other points (antinodes), the amplitude of the incident wave and the reflected wave amplify each other. The respective distance between the nodes and antinodes are shown in the bottom right of the Figure and expressed in terms of wavelength.
Figure 3. Amphidromic system of the M2 constituent in the North Sea. The light-blue lines are lines of equal tidal phase for the vertical tide (surface elevation) along such a line, and the amphidromic points are denoted by 1, 2 and 3.