1. Waves in the Ocean Words from these PPT slides are already on the course web site. Waves in the Ocean Words from these PPT slides are already on the course web site.

2. Wave Parameters

3. Properties of Ocean Waves ¥ An ocean wave is an undulation of the sea surface. –Wave crest –Wave trough –Wave height –Wave length –Wave period ¥ Progressive waves move across the sea surface. ¥ Standing waves oscillate about a fixed point.

4. What Causes Waves? ¥ Wind ¥ Submarine disturbance ¥ Gravitational attraction of sun and moon

5. Wind Generation of Waves ¥ Wind velocity ¥ Wind duration ¥ Fetch (distance over which wind blows) ¥ Simply put, wave size increases as all these factors increase.

6. Progressive Waves ¥ Wind-generated waves are progressive waves because they travel across the sea surface.

7. Progressive Wave Types ¥ Sea - irregular waves in the area of generation ¥ Swell - more regular waves beyond area of generation ¥ Surf - waves that have reached the coast, grow in height, and break

8. Wave Motions ¥ Forward movement of the wave form. ¥ Orbital motion of water particles beneath the wave. ¥ It is wave energy, NOT water molecules, that moves across the sea surface.

9. Flow of Energy, not Mass

10. Wave Motion with Depth

11. Motion Animation

12. Deep Water Waves Waves do NOT interact with the seafloor. Orbits of the water molecules are circular.

13. Shallow Water Waves Waves DO interact with the seafloor. Orbits of the water molecules become elliptical.

14. Life History of Ocean Waves

15. ¥ Waves originate in the fetch area. This area is characterized by a “confused” sea state with extensive wave interference. This interference may be –Constructive –Destructive

16. Rogue Waves? ¥ Constructive wave interference - wave buildup

17. Rogue Waves http://bit.ly/cs1I9bhttp://bit.ly/9XWFZuhttp://bit.ly/dmFsI7

18. Destructive Waves ¥ Destructive wave interference - wave cancellation

19. Progressive Wave Types ¥ Sea - irregular waves in the area of generation ¥ Swell - more regular waves beyond area of generation ¥ Surf - waves that have reached the coast, grow in height, and break

20. Transformation of Deep-water Waves: Dispersion

21. Shallow Waves Affected by Bottom ¥ In shallow water, the sea bottom transforms the wave’s properties. This leads to wave refraction and waves collapse forming surf (breakers).

22. ¥ Bending of the wave crest as waves enter shallow water. It is due to –Drag along the bottom. –Differential speed along the crest. Wave Refraction

23. Refraction Animation

24. Shallow-water Wave Transformations ¥ Interaction with the sea bottom. ¥ Bottom friction alters both the –Wave form ¥ Wavelength shortens (decreases) ¥ Height increases –Celerity (speed of wave form) ¥ decreases

25. Transformation of Shallow-water Waves

26. Progressive Wave Types Sea Swell Surf

27. Surf’s Up! Spilling Plunging, or Surging ¥ depending on the slope of the bottom

28. Back to Mavericks, CA Condition Black Video

30. Motion of Water Particles Beneath Waves