Florida: Exploring Teaching Resources for Science
1 of 9
Waves in the Ocean
In this document we will discuss three types of waves: wind-driven waves, tides and tsunamis. When the wind blows on the surface of the ocean it produces ripples, waves, and swell. Gravitational forces (mostly from the moon and sun) plus centrifugal forces in the solar system produce tides. Tectonic forces such as earthquakes that cause vertical displacements of the ocean floor, submarine volcanic eruptions, landslides and meteorite impacts on the ocean all cause tsunamis. The typical periods, wavelengths, and forcing mechanisms of the waves in the ocean that we discuss are presented in the following table. Name Ripples Sea Swell Typical Periods <0.2 sec 0.2 - 9 sec 9 - 30 sec Wave lengths 10
-2
Forcing mechanism wind on sea surface wind on sea surface wind on sea surface seismic
m
130 m 100s of meters few 100s of km
Tsunamis 15 minutes - 1 hour Tides several hours
several 100s - few 1000s km gravitational (mainly sun and moon)
The first class of waves that we will cover is that produced by the wind blowing on the oceans surface. Wind can generate waves locally, called sea, which travel in different directions and at different speeds. Wind can also generate waves that travel from a remote location in the open ocean, called swell, which travel in one direction and are more regular than sea waves. Ripples are the smallest and most irregular undulations produced by wind on the sea surface. To study wind waves, we should use ideal waves with sinusoidal shape. We define the properties of waves from these ideal waves (Figure 1). The wave crest is the point of maximu...
waves