Long description
This shows 2 complete cycles of a sinusoidal wave on the surface of water. There is a horizontal line halfway between peaks and troughs, the flat sea surface. L is the distance between 2 similar points e.g. 2 peaks and H is the vertical distance from peak to trough. d is the depth from the sea bed to flat sea surface. Waves move from the left with wave speed c subscript w. The coordinate axis is x positive to the right and z positive vertically upwards.