progressive waves. The waves reflect due to changes in water depth (for example when entering shelf seas) and at coastal boundaries. The result is a reflected wave that propagates in the opposite direction to the incident wave. The combination of the reflected wave and the incident wave is the total wave. Due to resonance between the reflected and the incident wave, the amplitude of the total wave can either be suppressed or amplified. The points at which the two waves amplify each other are known as antinodes and the points at which the two waves cancel each other out are known as nodes. Figure 2 shows a λ resonator. The first node is located at λ of the total wave, followed by the next node reoccurring λ farther at λ. A long, progressive wave travelling in a channel on a rotating earth behaves differently from a wave travelling along a non-rotating channel. Due to the Coriolis force, the water in the ocean is deflected towards the right in the northern hemisphere and conversely in the southern hemisphere. This side-way component of the flow due to the Coriolis force causes a build-up of water that results in a pressure gradient. The resulting slope develops until it is equilibrium with the Coriolis force; resulting in geostrophic balance. As a result of this geostrophic balance, Kelvin waves (originally described by Lord Kelvin) and Poincaré waves are generated. The amplitude of a Kelvin wave is highest near the coast and, when considering a wave on the northern hemisphere, decreases to further away from its right-hand coastal boundary. The propagation of Kelvin waves is always alongshore and its amplification falls off according to the Rossby radius of deformation. In contrast, Poincaré waves are able to propagate both alongshore as a free wave with a propagating wave pattern and cross-shore as a trapped wave with a standing wave pattern. Infinitely long channel In an infinitely long channel, which can be viewed upon as a simplified approximation of the Atlantic Ocean and Pacific Ocean, the tide propagates as an incident and a reflective Kelvin wave as shown in Animation 1. The red coloured lines indicate high tide and the blue coloured lines indicate low tide. Furthermore, the vectors field below the basin in Animation 1 show the direction and the strength of the tidal current. The amplitude of the waves decreases further away from the coast and