Waves

Waves represent the horizontal motion of water in the ocean, where the water itself doesn't move, but the wave trains do. Waves are actually the energy, not the water as such, which moves across the ocean surface. Water particles only travel in a small circle as a wave passes. Wind provides energy to the waves. Wind causes waves to travel in the ocean and the energy is released on shorelines. The motion of the surface water seldom affects the stagnant deep bottom water of the oceans. As a wave approaches the beach, it slows down. This is due to the friction occurring between the dynamic water and the sea floor. And, when the depth of water is less than half the wavelength of the wave, the wave breaks. The largest waves are found in the open oceans. Waves continue to grow larger as they move and absorb energy from the wind. Most of the waves are caused by the wind driving against water. When a breeze of two knots or less blows over calm water, small ripples form and grow as the wind speed increases until white caps appear in the breaking waves. Waves may travel thousands of km before rolling ashore, breaking and dissolving as surf. A wave’s size and shape reveal its origin. Steep waves are fairly young ones and are probably formed by local wind. Slow and steady waves originate from far away places, possibly from another hemisphere. The maximum wave height is determined by the strength of the wind, i.e. how long it blows and the area over which it blows in a single direction. Waves travel because wind pushes the water body in its course while gravity pulls the crests of the waves downward. The falling water pushes the former troughs upward, and the wave moves to a new position The actual motion of the water beneath the waves is circular. It indicates that things are carried up and forward as the wave approaches, and down and back as it passes.

Waves play a vital role in ocean dynamics, coastal processes, and marine ecosystems. Waves are an integral part of the ocean's dynamic system, playing a critical role in the exchange of heat, energy, and nutrients. They also influence coastal morphology, sediment transport, and the distribution of marine life. Understanding wave behavior and characteristics is essential for coastal engineering, navigation, and marine safety. Here are some key aspects of waves:

Wave Formation:

• Wind Waves: The most common type of waves is wind waves, which are generated by the frictional drag of wind blowing across the water's surface. The size and energy of wind waves depend on factors such as wind speed, duration, and the fetch (the distance over which the wind blows).
• Seismic Waves: Earthquakes and underwater volcanic eruptions can generate seismic waves that propagate through the water, creating tsunamis.

Characteristics of Waves:

• Crest and Trough: Waves have crests, which are the highest points of the wave, and troughs, which are the lowest points between crests.
• Wavelength: The distance between two consecutive wave crests is the wavelength. Longer-wavelength waves are generally associated with swells, while shorter-wavelength waves are wind waves.
• Wave Amplitude: It is one-half of the wave height.
• Wave Height: The wave height is the vertical distance between the wave's crest and trough. It is influenced by the wind's energy and the distance over which the wind blows (fetch).
• Wave Speed: It is the rate at which the wave moves through the water and is measured in knots.
• Wave Frequency: It is the number of waves passing a given point during a one-second time interval.
• Wave Period: The wave period is the time it takes for two consecutive wave crests to pass a fixed point. It is a measure of the time between wave crests and is inversely related to wave frequency.

Types of Waves:

• Wind Waves: Wind waves are the result of local or distant winds. They can range from small ripples to large, powerful swells.
• Swells: Swells are long-period waves with longer wavelengths that result from distant storms. They can travel across entire ocean basins, carrying energy from one region to another.
• Tsunamis: Tsunamis are seismic sea waves generated by underwater disturbances, such as earthquakes, volcanic eruptions, or landslides. Unlike wind waves or swells, tsunamis have very long wavelengths but low wave heights in deep water. However, they can grow significantly in height as they approach shallow coastal areas.

Wave Energy and Power:

• Waves carry energy across the ocean surface, which can be harnessed for various purposes, such as wave energy conversion for electricity generation.
• The power of a wave depends on its wave height and period. High-energy waves can have significant impacts on coastlines, causing erosion and flooding.