Understanding Surface Waves

A surface wave is an oscillatory disturbance that moves across the sea's surface.
When a wave travels, it propagates the wave form (energy) however no real mass transfers occur.
Energy travels along the interface between the ocean and atmosphere

Crest is the highest part of the wave above mean sea-level
Trough is the lowest part under mean sea-level
Wavelength (L) [m] is the horizontal distance between two successive crests, or troughs
Wave height (H) (m) is the vertical distance displacement between a crest and the adjacent trough
Amplitude (a) [m] is the maximum displacement from the mean sea-level
Wave period (T) [s] is the time interval between the passage of two successive crests at a fixed point
Frequency (f) [Hz] is the number of crests passing a fixed point per second

Relative depth is the ratio of water depth to wavelength (= h/L)
When h/L is greater than or equal to ≥ (1/2), the wave is considered a Deep-water wave
When h/L is less than or equal to ≤ (1/20), the wave is considered a Shallow-water wave
Transnational waves occur when (1/20) < h/L < (1/2).

Water depth is < (1/20)L
Orbital motion is getting squished by the Bottom into ellipses that approximate Back and forth motion near the bottom
Wave speed (celerity) proportional to the depth of the water
Wave speed (C) can be calculated with √g * h

Sea waves are random waves inside the storm area under wind action
They have varying wave heights, lengths, periods, and directions
Height increases faster than the length, causing the wave to become unstable and break (whitecaps)

Swell features uniform, symmetrical waves that travel outward from the storm area
They are faster than the wind outside the storm causing the wave heights to decrease
Swell transports longer wavelength energy over long distances

When deep-water swell waves approach shore, they shoal by moving over increasingly shallow water
Wave speed decreases
Wavelength decreases
Wave height increases
Wave steepness increases
Waves break

When waves approach barriers with gaps, the wave will spread or disperse upon passing through the gap.
When waves approach a barrier with multiple gaps, wave diffraction will occur, as the wave passes through each gap, and the spreading waves may interact both destructively and constructively.
Barriers with many gaps can scatter wave energy which diminishes waves height and power

Internal waves form on the interface between two layers of different densities (the surface of density discontinuity)
Internal waves form within the water column on the pycnocline
Disturbances to the pycnocline can generate internal waves, including the flow of water related to tides, flow of water masses past each other, storms, or submarine landslides
Properties of progressive waves displayed are reflection, refraction, interference, breaking, etc
Wave properties are different compared to surface waves due to the small density difference between the water masses above and below the pycnocline

Tsunamis come from the Japanese word for harbor wave
They are a series of huge waves that can cause great devastation and loss of life
Tsunamis were previously called tidal waves, but are unrelated to tides
They only become a danger when reaching coastal areas where the wave height can reach 30 m or greater
Tsunamis originate from earthquakes, volcanic explosions, or submarine landslides
They have long wavelengths (> 200 km or 125 miles)
Tsunamis are shallow-water waves
Speed is proportional to water depth, making them very fast in the open ocean reaching a max speed = 800 km/hr
Sea level can rise up to 40 m (131 ft) when a tsunami reaches shore
Usually creates a surging front of water at the shoreline instead of a breaking wave,
Includes a sudden extreme high tide (hence originally called tidal waves) and a sudden recession of water before the surge
Several surges occur due to the series of waves
The wave velocity or speed depends on the depth
The formula for wave velocity = √(g * h) where g = gravity acc. and h = depth of the earthquake