1. Waves and Tides MOTION IN THE OCEAN

2. Waves  A disturbance which moves through or over the surface of a fluid  Mostly caused by: WindsEarthquakes Gravitational Pull Volcanos  Form of great energy

3.  When a wave passes through the ocean, individual water molecules move up and down but they do not move forward or backward.

7. http://www.military.com/video/logistics-and- supplies/naval-equipment/warship-takes- on-massive-waves/1910420040001http://www.military.com/video/logistics-and- supplies/naval-equipment/warship-takes- on-massive-waves/1910420040001/

8.  http://oceanexplore r.noaa.gov/edu/lear ning/player/lesson0 9.html http://oceanexplore r.noaa.gov/edu/lear ning/player/lesson0 9.html http://oceanexplore r.noaa.gov/edu/lear ning/player/lesson0 9.html

9. Wave Characteristics  Parts of a Wave Crest = high point Crest = high point Trough = low point Trough = low point Height = vertical distance from crest to trough Height = vertical distance from crest to trough Wavelength = Horizontal distance between crest to crest or trough to trough Wavelength = Horizontal distance between crest to crest or trough to trough

10. Size of Wind Generated Waves  Depends on 3 things : Wind Speed Wind Speed Wind Duration (length of time wind blows) Wind Duration (length of time wind blows) “Fetch” Extent of open water across which the wind can blow “Fetch” Extent of open water across which the wind can blow

11. Water Motion in Waves  Water travels in vertical circular orbits  Wave moves, particles don’t!

12. Importance of Waves  Shaping Coastlines Erode cliffs Erode cliffs Grind rock into sand Grind rock into sand  Ecology Returns O 2 to water Returns O 2 to water Stir up food for filter feeders Stir up food for filter feeders

13. Types of Waves CHOP – Short period (back bays) SWELL – Long period (boat rolls; seasickness) SWASH – water up beach BACKWASH – back down

14. Caused by undersea quake or volcano Wavelength = ~150 mi. Wave height = 6” – 1’ Can NOT perceive in boat Speed > 500 mph Slows down to ~25 mph at shore; water builds up to ~65+ ft TSUNAMI “TIDAL WAVE”

15. Tsunami Waves

16. Creation of a Tsunami

17. Before the 2004 Indian Ocean tsunami reached Sri Lanka, many animals, like this elephant, moved to high ground and survived The man on the left is about to be killed by the tsunami that struck Hilo, Hawaii in 1946.

18. Hundreds of thousands of people died in the December 26, 2004 Indian Ocean tsunami. But as described in these news reports, others saw warning signs, and escaped with their lives. Thousands died on the beaches of Thailand in the December 2004 tsunami. But a 10-year-old British girl saved more than 100 people because she had just studied the killer waves in school. When the sea suddenly began to boil, then pulled away from the resort she was visiting, leaving fish and boats stranded high and dry, Tilly Smith recognized that a tsunami was approaching. Fortunately, her frantic warnings were heeded, and the beach was evacuated just moments before the huge waves crashed ashore. Kalutara Beach Detail Imagery collected December 26, 2004. Description: Receding waters and beach damage from tsunami

19. " Primitive" Tribe Survives Tsunami Off the coast of India, the remote Andaman Islands are home to the aboriginal Onge (pronounced OHN-ghee) a tribe that follows an ancient hunter-gatherer lifestyle. On December 26, 2004, when the creek that ran through their settlement suddenly went dry and the sea pulled away from the shore, the Onge took immediate action. Believing that evil spirits were at work, the tribe scattered pig and turtle skulls around their settlement and threw stones into the sea, then quickly gathered their possessions and ran inland. Moments later, a tsunami slammed into the island of Andaman. All 96 Onge survived the tsunami because of their awareness of natural processes. Many other people in the region were less attuned to nature, and paid with their lives. When the seabed was exposed by the approaching tsunami, tourists visiting the coast of Thailand wandered curiously toward the receding ocean, and Indonesian fisherman ran to pick up fish left high and dry, oblivious to the danger.

20. TABLE TALK   Apparently, some animals are alerted to the approach of a large tsunami in ways that humans can't detect. Speculate about what warning signs animals might pick up that people cannot.   Describe several warning signs that often precede tsunami.   Why do you think so many people ignore these indicators?   If you detect any tsunami warning signs, what should you do?

21.  http://www.onr.navy.mil/focus/ocean/motio n/waves1.htm http://www.onr.navy.mil/focus/ocean/motio n/waves1.htm http://www.onr.navy.mil/focus/ocean/motio n/waves1.htm

24. Early thoughts about what caused the tides.  Some believed the earth was a living animal and the tides a result of its breathing.  Others, who thought the ocean’s waters were the earth’s blood, decided the tides were its pulse, caused by the beating of its great heart.

25. Early thoughts about what caused the tides.  Early followers of the religious prophet Muhammad believed that the rise and fall of the waters were caused when the “Angel of the Sea” placed his foot in and out of the ocean.  Primitive natives thought the tides were a sign of a sea god’s anger and made human sacrifices to please him.

26. Sir Isaac Newton to the Rescue!  Newton’s Universal Gravitation theory helped to explain how the gravity of the moon (and the sun) were related to tides.

27. Tides  The rhythmic rise and fall of the ocean’s water High tide = rising, incoming tide, flow Low tide = receding, outgoing tide, ebb Slack tide = vertical movement stops

31. http://oceanexplorer.noaa.gov/edu/learning /player/lesson10.html

32. 1. Gravitational pull of sun & moon on Earth What Causes Tides? Moon closer, therefore > effect Like magnet, pulls water away from surface = TIDAL BULGE http://oceanservice.noaa.gov/education/kits /tides/media/supp_tide04.html

33. Tides are generated by: the gravitational pull of the moon and sun - moon has 2x greater gravitational pull than the sun - sun is 10 million x more massive than the moon and is 390 times farther away

34.  Tides are very long, slow waves They have a wave period of 12 hours 25 min They have a wave period of 12 hours 25 min Tidal day is 24 hours 50 min Tidal day is 24 hours 50 min NJ has 2 high and 2 low tides daily NJ has 2 high and 2 low tides daily

35. 2. Centrifugal Forces Produced by motions of Earth, sun, & moon Bulge on opposite side because centr. force > pull of moon

36. Centripetal force

37. Types of Tides 2x’s/month 2x’s/month Spring Tide - Moon and sun are in direct line with one another - Results in unusually high tidal range -Tidal Range = vertical distance between high & low tides

38.  Neap Tide sun and moon are at right angles sun and moon are at right angles Pulls cancel each other out – causes a weak pull Pulls cancel each other out – causes a weak pull unusually low tidal range unusually low tidal range 2 x’s / month 2 x’s / month

39. Spring vs. Neap Tides http://oceanservice.noaa.gov/education/kits /tides/media/supp_tide06a.html

40. The monthly tidal cycle (29½ days) About every 7 days, Earth alternates between: Spring tide Spring tide Alignment of Earth-Moon-Sun system (syzygy)Alignment of Earth-Moon-Sun system (syzygy) Lunar and solar bulges constructively interfereLunar and solar bulges constructively interfere Large tidal rangeLarge tidal range Neap tide Neap tide Earth-Moon-Sun system at right angles (quadrature)Earth-Moon-Sun system at right angles (quadrature) Lunar and solar bulges destructively interfereLunar and solar bulges destructively interfere Small tidal rangeSmall tidal range

41. Distance bet. Moon & Earth Perigee Tides Perigee Tides Moon closest to earth, very high tides (causes flooding)Moon closest to earth, very high tides (causes flooding) Apogee Tides Moon farthest away from earth, very low tidesMoon farthest away from earth, very low tides

43. Types of Tides Continued  Diurnal Tides 1 high & 1 low / day 1 high & 1 low / day Parts of Gulf of Mexico and Asia Parts of Gulf of Mexico and Asia  Semi-Diurnal Tides 2 high & 2 low / day 2 high & 2 low / day Atlantic coasts of North America and Europe Atlantic coasts of North America and Europe  Mixed 2 high & 2 low / day (height varies) 2 high & 2 low / day (height varies) Pacific coast Pacific coast

45. http://oceanservice.noaa.gov/education/tut orial_tides/media/supp_tide01.html

46. Importance of Tides Expose & submerge orgs Circulate water in bays & estuaries Trigger spawning (grunion, horseshoe crab) Circulates food, wastes, etc

47. Impacts of Tides Predicting tides has always been important to people who look to the sea for their livelihood. Commercial and recreational fishermen use their knowledge of the tides and tidal currents to help them improve their catches. Depending on the species and water depth in a particular area, fish may concentrate during ebb or flood tidal currents. In some areas, strong tidal currents concentrate bait and smaller fish, attracting larger fish. In addition, knowledge of the tides has also been of interest to recreational beachgoers and surfers.

48. Currents What are currents? - “Rivers” of circulating water Causes - Wind - Rotating Earth - Density Changes

49. Ocean Circulation  Currents are also a product of the wind.  Current can be in surface layers of deeper water layers  Both winds and the currents they drive are affected by the Coriolis Effect.  Because the earth spins continuously, anything that passes over the earth is deflected.

50. Ocean Circulation  In the northern hemisphere, winds and currents are deflected to the right.  In the southern hemisphere, winds and currents are deflected to the left.  This deflection termed the Coriolis Effect. Since the Earth is spinning, it causes this defection of winds and currents.  This deflection often causes currents to travel in circular patterns called gyres.

52. Coriolis Effect - N. Hemis – clockwise; Right - S. Hemis – counterclockwise; Left

53. https://www.youtube.com/watch?v=i2mec3 vgeaI Coriolis Effect https://www.youtube.com/watch?v=Pb69H ENUZs8 http://video.mit.edu/watch/the-coriolis- effect-4407/

54. Ocean Circulation  Despite repeated mixing by winds and currents at the ocean’s surface, the ocean is still stratified into three layers: – Surface layer – from surface to about 200 meters; this layer stays well mixed most of the year. – Intermediate layer - from 200 – 1500 meters; major temperature change (thermocline) is located here. Less mixing occurs here. – Bottom layer – below 1500 meters; low mixing and normally uniformly cold.

55. Deep Ocean Currents DRIVE THE OCEAN CONVEYOR BELT  Separated from surface currents by boundary called a “Thermohaline”  Flow beneath surface; cross equator  Move North to South

56. In some locations, large volumes of water may sink or rise. Water sinks due to changes in temperature and salinity – this is known as an area of down-welling. Down-welling brings gases from the surface to deeper layers.

57. Importance Of Deep Currents Upwelling Upwelling Brings deep water to surf.Brings deep water to surf. Circulates nutrients upCirculates nutrients up Moves plankton & larvaeMoves plankton & larvae

60. Surface Ocean Currents Broad, slow drifts; never cross equator Wind generated; circular gyres

61. Gulf Stream - Brings warm water from equator north along east coast of N. A. - N. Atlantic -Sometimes form eddies – circulating water that pinches off from the current

62. MIGRATION NAVIGATION WEATHER

63. Localized Surface Currents Longshore Current. Flows parallel to shore; move sediment Flows parallel to shore; move sediment

64. RIP CURRENT - Caused by converging longshore currents - Very dangerous ; Red Flag - DO NOT fight rip current; swim parallel to shore to get out of channel

65. http://www.deepseanews.com/2012/06/mu st-watch-video-on-rip-currents/

67. http://www.hamilton.k12.nj.us/webpages/as chwing/resources.cfm?subpage=358703www.hamilton.k12.nj.us/webpages/as chwing/resources.cfm?subpage=358703