1 / 40

Unit 4- Physical Oceanography

Unit 4- Physical Oceanography. Currents. Ocean current- mass of ocean water that flows from one place to another Two types Surface/wind-driven Deep/density-driven. Coriolis Effect. Coriolis Effect- a “deflection ” of a moving object due to the fact that the Earth is rotating

fredrickk
Download Presentation

Unit 4- Physical Oceanography

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 4- Physical Oceanography

  2. Currents • Ocean current- mass of ocean water that flows from one place to another • Two types • Surface/wind-driven • Deep/density-driven

  3. Coriolis Effect • Coriolis Effect- a “deflection” of a moving object due to the fact that the Earth is rotating • Moving object travels in straight line from outside reference, but Earth has moved underneath, so object appears to move in a curved path • Objects are deflected to the RIGHT in the Northern Hemisphere and to the LEFT in the Southern Hemisphere • No effect at the Equator and maximum effect at the poles

  4. http://www.youtube.com/watch?v=mcPs_OdQOYU

  5. Global Winds • Winds named based on where they are coming from • Northern Hemisphere winds: • Polar Easteries • Prevailing Westerlies • NE Trade Winds • Southern Hemisphere winds: • Polar Easterlies • Prevailing Westerlies • SE Trade Winds

  6. Waves • Three main causes of ocean waves • 1. Wind* • 2. Tides • 3. Seismic Activity (earthquakes, volcanoes) • http://www.youtube.com/watch?v=dv_Sis0Hntk&feature=player_embedded • http://www.youtube.com/watch?feature=player_embedded&v=aXuQC1qRuEM

  7. Waves • Other factors affecting wave height • Distance from shoreline • Latitude • Water depth • Nearby landmasses

  8. Wave Energy • http://www.youtube.com/watch?v=7k5r89IseEM

  9. Tides • Definition – low, earth-wide waves that cause regular rise/fall in sea level • Take place every 12 hours and 25 minutes; therefore, they are predictable • Vary in height (from 1-20 meters)

  10. http://www.youtube.com/watch?v=6IyRE9azhwQ&feature=player_embedded#!http://www.youtube.com/watch?v=6IyRE9azhwQ&feature=player_embedded#!

  11. Causes of Tides 1. Gravity • Moon pulls water towards it, creates bulge on moon side of earth • Sun- same thing, but only about 1/3 – 1/2 the effect; responsible for extra high tides

  12. Causes of Tides 2. Inertia (centripetal force) • Things want to keep moving in straight line • “Counteracts” the force of gravity from moon • Causes opposite bulge on far side of earth

  13. Two high tides & two low tides per day • Time of high/low tide depends on the lunar cycle

  14. Types of Tides • Flood- when tide is coming in (change from a low to high tide) • Ebb- when tide is going out (change from a high to low tide) • http://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide01.html

  15. Types of Tides • Spring- very strong tides, due to alignment of Earth, sun, and moon (straight line) • Neap- very weak tides, due to alignment of Earth, sun, and moon at 90° angle (effects cancel) • http://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide06a.html

  16. Lunar Cycle- 29.5 days When would spring tides occur? When would neap tides occur?

  17. Lunar Cycle & Tides • Spring tides- new moon and full moon • Neap tides- 1st quarter moon and 3rd quarter moon • Spring & Neap occur once every 14 days • http://stardate.org/nightsky/moon

  18. http://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide05.htmlhttp://oceanservice.noaa.gov/education/tutorial_tides/media/supp_tide05.html

  19. Tidal Bore • Tidal bore occurs when a river runs backwards due to incoming tide and land formation around it

  20. Importance of Tides • Mix shallow waters • Move floating organisms into/from breeding areas • Fisheries, ships, recreation

  21. http://bayoffundy.com/about/highest-tides/

  22. Tsunamis • Tsunami- underwater seismic activity that transfers lots of energy into a water column • Ex.- Earthquakes, volcanoes, avalanches • Drawback- trough of wave reaches shore before the crest, so water along the shoreline recedes dramatically • Waves slow down as they reach the shore, increasing in height • http://upload.wikimedia.org/wikipedia/commons/2/2d/Propagation_du_tsunami_en_profondeur_variable.gif

  23. Tsunamis: Coastal Impacts • Not a huge breaking wave, rather a strong flood • Extreme destruction • Marine life washed ashore • Often injuries and casualties

  24. http://www.youtube.com/watch?v=BsRd7WQuBHc

  25. http://www.pbs.org/teachers/connect/resources/6723/preview/

  26. ENSO Cycle • ENSO (stands for El Niño/ Southern Oscillation) Cycle: • Year-to-year variations in temperature, rainfall, air pressure, circulation, etc. • Occurs in the equatorial Pacific • Highly irregular pattern • The cycle can last anywhere from 2-10 years

  27. El Niño • Refers to the above average sea-surface temperatures that periodically develop across the east-central equatorial Pacific • Represents the warm phase of the ENSO cycle • Cause: equatorial easterly trade winds diminish, resulting in an eastward shift of the Pacific warm pool

  28. How El Niño Affects Global Climate • Warmer winters across the northern U.S. • Gulf states cooler and wetter • Increases storms on the west coast of North & South Americas • Fisheries disrupted • Can cause a drought in Indonesia and western Pacific

  29. La Niña • Periodic cooling of sea-surface temperatures • East-central equatorial Pacific • Represents the cold phase of the ENSO cycle • Equatorial easterly trade winds strengthen

  30. How La Niña Affects Global Climate • La Niña has equally dramatic, often opposite effects of El Niño • Could increase the number of Atlantic hurricanes • Where there was drought, now turns to flooding; flooding turns to drought • Abnormally mild winter now turn to abnormally harsh winter

  31. 2011 La Niña • Major snowfall • Extreme flooding/high river levels • Severe drought in Southwest • Joplin/Tuscaloosa tornados • Warmer temperatures in the fall

  32. Tropical Cyclone • Huge rotating masses of low pressure • Generate strong winds and torrential rain • Called hurricanes in North and South America • Called typhoons in Pacific • Called cyclones in Indian Ocean

  33. Hurricane Conditions • Warm ocean water • Warm moist air • Coriolis Effect- causes hurricanes to spin • Found during late summer and early fall • Hurricane season: June 1- November 30

  34. Hurricane Movement • Driven by trade winds • Move east to west across oceans • Eye of the hurricane- winds are drawn upward, so horizontal wind speeds are low= usually calm • Composed of spiral rain bands that create intense rainfall • Movement over land cuts off energy source

  35. Hurricane Destruction • Caused by high winds and flooding from intense rainfall • Storm surge- extremely high winds cause water to pile up higher than normal sea level • Main cause of destruction

  36. Tropical Cyclone Destruction • Deadliest Storm: • Great Bhola Cyclone- 1970, Bangladesh killed 500,000 people • Top 30 deadliest tropical storms all occurred in Indian Ocean or western Pacific near China

  37. U.S. Hurricanes • Deadliest: • 1. Galveston Hurricane- 1900 in Galveston, TX killed over 6,000 people • Deadliest natural disaster in US history • 3. Hurricane Katrina- 1000 deaths • Most damaging: • Hurricane Katrina- 2005, caused over $100 billion in damage • Hurricane Sandy- 2012, caused $50 billion in damage

  38. http://www.youtube.com/watch?v=YeutC1WN6dc

More Related