Waves and how they are affected as they approach the shore

They are high energy because the storm means there is a lot more energy to be transferred to the sea from the winds. One form of sea wave that occurs is known as a rogue wave. These rogue waves, or freak waves, are large, spontaneous storm waves. Storm Waves are frequent in environments known as ‘regions of cyclonic frontal activity’ which are in the higher mid latitudes of both hemispheres Swell Waves move out from a storm, the further these waves travel, the weaker, the less energy, these waves have. These waves have a relatively low height compared to their large wavelength. Swell waves are far more regular than Strom Waves and have a lower frequency. They are released from the storm in all directions and can travel for hundreds of miles. Sea Waves are locally generated in relatively sheltered area of sea. They are formed by light winds, no more than force two or three; they are also irregular and can often break. These do not break by exceeding the critical steepness, the wind simply blows the top off the wave causing white water to be formed on the top of the waves, and these are known as ‘White Horses’. Sea Waves are high frequency and can be destructive. There is another form of wave that is not formed by anything to do with the wind, these waves are called Tsunamis. They are formed by tectonic action. An oceanic plate sub-ducts under a continental plate, or another oceanic plate, the plate doesn’t move down smoothly. The pressure builds up and the plate will suddenly slip. All the water in the trough that was made is pushed up in a short period of time. This huge wave travels through the ocean with immense energy. When waves approach the shore they remain unchanged until they reach shallow water, water that is shallow enough that the lowest orbital produced from the wave is touching the bed of the sea. This is when the wave behaves in a different manner. The base of the wave is slowed due to friction between its lower orbitals and the seabed. This causes the wave to slow down and therefore the wavelength is shortened. The height of the wave increases, meaning it is getting steeper. The wave will reach its critical steepness and as it exceeds this it will ‘break’. This is not the only way in which wave approaching a beach can break. Another way in which a wave can break is by the friction of the lower orbitals interacting with the seabed and slowing down, as the lower part of the wave slows down the top remains moving at the same speed and thus will ‘topple over’ or break. The third way a wave can be caused to break is as it comes in to the shallower water and slows down, gets higher and becomes asymmetrical the wave will become so asymmetrical that the orbitals will not be able to complete their circular pattern as there is no water and the wave will break. The kinetic energy the water has in the wave will be transferred and used up in other processes. Sound is produced and the particles on the beach are moved, also heat is produced although this is a minimal amount of the usage of the energy from the wave. Not all waves coming in to the shoreline will be breaking on a beach. Cliff lines will meet many of them. The wave behaves differently when it comes in to a cliff than it does to a beach. The cliffs will not be in a perfectly straight line, there is likely to be headlands and bays. As the wave reaches the shallow water in front of these it will slow down, however it will reach the shallow water in front of the headlands before it reaches the shallow water in the bays. This means the wave will effectively be focused on to the headlands and the energy of the wave is dissipated in the bay. This is refraction The wave will deposit its load in the bays as they are low energy and the high-energy waves that attack the headlands will erode it, this process is known as ‘regularisation’. Regularisation is effectively the straightening out of the coastline.