SCM 330 Ocean Discovery through Technology

1. SCM 330 Ocean Discovery through Technology Area F GE

2. Introduction To Marine Science Goals: Background of the Dynamic Processes at work in the Ocean.

3. Physical Oceanography Circulation Waves Tides

4. Physical Oceanography - Circulation Major Ocean Currents

5. Physical Oceanography - Circulation Ocean Circulation Surface Circulation Dynamics

6. Physical Oceanography - Circulation Surface Ocean Circulation Surface Currents are Wind Driven

7. Physical Oceanography - Circulation WIND Depth (Z) 2000 m Transfer ofEnergy by friction Drive surface currents Wind stress + Coriolis + Gravity

8. Physical Oceanography - Circulation The Ekman Spiral

9. Physical Oceanography - Circulation How Water is Effected by Wind

10. Physical Oceanography - Circulation Gyre Formation

11. Physical Oceanography - Circulation

12. Physical Oceanography - Circulation Gyre Formation

13. Physical Oceanography - Circulation Pressure Within A Gyre

14. Physical Oceanography - Circulation

15. Physical Oceanography - Circulation Equatorial Current Dynamics

16. Physical Oceanography - Circulation Water piles up the equatordue to NEC and SEC Equatorial Current Dynamics

17. Physical Oceanography - Circulation • Largest Current (150 - 300 sv) • Feeds the Peru (Humbolt) and Benguela Currents Antarctic Circumpolar Current

18. Physical Oceanography - Circulation Differences Between Western and Eastern Boundaries

19. Physical Oceanography - Circulation Western Boundaries

20. Physical Oceanography - Circulation Africa N. America Differences Between Western and Eastern Boundaries

21. Physical Oceanography - Circulation Speed of Gulf Stream

22. Physical Oceanography - Circulation The Gulf Stream: • 33 - 90 sv // 250 cm/s 33 - 35 sv at Florida (narrow and shallow) 60 - 90 sv at Cape Hatteras (wide and deep)

23. Physical Oceanography - Circulation Kuroshio Western Boundary

24. Physical Oceanography - Circulation Small Scale Dynamics: Langmuir Cells Up to ~ 2 km long

25. Physical Oceanography - Circulation Langmuir Cells

26. Physical Oceanography - Circulation Ocean Circulation Deep – Driven by Differences in Density (Thermo-haline Circulation)

27. Mixed Intermediate Deep Water Physical Oceanography - Circulation Thermo-haline Circulation • Drives deep, ocean circulation, affecting almost 90% of Ocean’s total volume • Temp and Salinity affect density of water masses. Density  as Temp  and Salinity 

28. Physical Oceanography - Circulation Density differences

29. Physical Oceanography - Circulation Mixing Dynamics

30. Physical Oceanography - Circulation Density Temperature

31. Physical Oceanography - Circulation Important Water Masses

32. Physical Oceanography - Circulation MOVIE Conveyer Belt Circulation Can take 1,000 years to complete a lap

33. Physical Oceanography - Circulation El Niño (Southern Oscillation)

34. Physical Oceanography - Circulation Normal Conditions El Nino Conditions

35. Physical Oceanography - Circulation

36. Physical Oceanography - Waves Waves • Wave Movement • Wave Characteristics • Wind-Generated Waves • Tsunamis • Internal Waves

37. Where do Waves Come From? Physical Oceanography - Waves large weather systems and winds blow across water and cause waves Waves that travel long distances from the storm are Swell Waves

38. Development of Sea and Swell Physical Oceanography - Waves At the source, the wind pushes up large waves, called a forced sea As the waves travel away from the source, the wind no longer pushes them up, so they become smoother, shorter (called dispersion), and longer wavelength, and are called a swell

39. Wave Train Physical Oceanography - Waves A group of swell waves traveling together form a Wave Train Wave trains travel away from the storm center Travel distance depends on wind energy generated by the storm Short period waves damp out with distance, leaving longer period waves; so near a storm you see a mixture of long and short period swells, but only long period at a distance

40. Wave Motion Physical Oceanography - Waves • Waves move by the transmission of energy by cyclic movement through matter • The medium itself (water) does NOT travel • Wave motion is NOT water FLOW, but is a flow of energy • Progressive Waves • Can be longitudinal (push-pull), transverse (side to side), or orbital (interface waves) • Orbital waves are the most common type at the sea surface • Transmit energy along the interface of two fluids of different density (water and air)

41. Particle Motion Movie Physical Oceanography - Waves http://www.esam.northwestern.edu/research/about_waves.html

42. Wave Characteristics Physical Oceanography - Waves Direction of motion Wavelength (L) = horizontal distance between successive peaks or troughs Wave height (H) = vertical distance between peak and trough Crest = top of wave Trough = bottom of wave Frequency (f) = number of wave crests passing a point in unit time (second) Period (T) = time required for wave crest to travel one wavelength Steepness (S) = ratio of wave height to wavelength (H/L) Speed = wavelength divided by period (L/T)

43. Physical Oceanography - Waves More Wave Characteristics • There is a slight net movement of water in • the direction of the wave because particle • speed decreases with depth • Deep-Water Waves occur where water depth (d) is greater than L/2 • Are not affected by ocean floor • Speed is determined by L and T • T easiest to measure, so speed is calculated by S = 1.56*T • This applies to most wind waves

44. Speed of Deep Water Waves Determined by Wavelength Physical Oceanography - Waves

45. Wave Summary Physical Oceanography - Waves

46. Physical Oceanography - Waves

47. Physical Oceanography - Waves Shallow & Transitional Waves Transitional Waves (20d < L < 2d) speed is controlled by wavelength and water depth • Shallow-water Waves occur where the water depth (d) is less than 1/20 of • the wavelength (L) • Includes wind waves that move inshore, tsunamis (seismic waves),and tides • (tide waves) • Speed equals 3.1 times the square root of the depth in meters, S = 3.1 *d • Particle motion is in the form of a flat, elliptical orbit

48. Physical Oceanography - Waves Shallow & Deep Water Waves Graph shows how wave speed depends on wavelength and whether a wave is shallow or deep water variety Deep water wave speed determined by wavelength Transitional waves are a combination Shallow water wave speed determined more by depth

49. Physical Oceanography - Waves Wind Generated Waves • Capillary Waves- the smallest waves formed at the lowest wind speeds • The restoring force (the force that pulls wave down) is surface tension • Gravity Waves- the next stage of waves formed by increasing wind speeds • Named for their restoring force (gravity) • Increasing energy from wind increases wave height, length, and speed

50. Physical Oceanography - Waves Factors That Increase Wave Energy • Major Factors that Increase Wave Energy • Wind Speed • Duration - amount of time that wind blows in one direction • Fetch - the distance over which wind blows in a single direction • Fully-Developed Sea - when the maximum fetch and duration are • achieved for a given wind speed