MEA 200 Lecture Notes - Lecture 12: Pycnocline, Air Interface, Wind Wave
30 Mar 2017
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Caused by tides, turbidity currents, winds, ships. Wave frequency: number of wave crests passing point a each second. Wave period: time required for wave crest at point a to reach point b. Wave forms appear to move when energy is transferred from water particle to water particle in an orbital motion. Diameter of orbital motion decreases with depth of water. Hardly any motion below wave base due to wave activity. Wave base depth where orbital movement of water particles stops. If water depth is greater than wave base (> l), wave is a deep water wave. Don"t feel the bottom, so movement stays orbital (circular) Orbits get flattened out by contact w/ sea floor as they move toward shore; become more elliptical than orbital. Characteristics of both deep- and shallow-water waves. Speed depends on both water depth and wavelength. Wavelengths are >2x but <20x the water depth. Perturbing force: wind; restoring force: surface tension. Fetch distance over which wind blows.
