The Movement of Ocean Water. Currents

Transcription

1 The Movement of Ocean Water Currents

2 Ocean Current movement of ocean water that follows a regular pattern influenced by: weather Earth s rotation position of continents

3 Surface current horizontal movement of ocean water caused by wind occurs at or near ocean s surface controlled by: global winds Coriolis effect continental deflections

4 Global Winds winds that blow across Earth s surface that create surface currents different winds cause currents to flow in different directions

5 Coriolis Effect Earth s rotation causes wind and surface currents to move in a curved path

6 Continental Deflections when surface currents meet continents, the currents deflect (change direction)

7 Taking Temperatures warm-water currents begin near equator carry warm water to other parts cold-water begins close to poles carry cold water to other parts

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9 Deep Currents stream-like movement of ocean water far below surface not controlled by wind forms where water density increases density affected by: salinity and temp

10 Increasing Density cold air chills water, increases density, cold water sinks Increasing Salinity (Freezing) when water freezes, salt gets squeezed out at surface and enters liquid below increases density

11 Increasing Salinity (Evaporation) warm climates, water evaporates, leaves salt behind increases density, sinks to form deep current

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13 Currents and Climate

14 Warm-Water Surface Currents Currents that create warm climates in coastal areas that would otherwise be much cooler

15 Cold-Water Keep coastal areas cooler than inland climate

16 Upwelling Movement of deep, cold, and mineral-rich water to surface of the ocean Nutrients support the growth of plankton and animals that eat plankton

17 El Niño Effects of El Niño Change in water temperature in the Pacific Ocean Produces a warm current Alters weather patterns Causes disasters (flash floods, mudslides, droughts) Prevents upwelling off the coast of South America

18 Studying El Niño La Niña La Niña Important due to its effects on land and on organisms Scientists use a network of buoys along the equator that record data Cooler than normal temperatures in the Pacific ocean El Niño

19 Waves

20 Anatomy of a Wave Wave Made up of crests and troughs Crest Highest point of a wave Trough Lowest point of a wave

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22 Wave Formation and Movement Wave Formation Wave Movement Most are formed when the wind blows and transfer its energy to the water As wind blows, water particles move up and down in circular motion The water itself stays behind

23 Specifics of Wave Movement Wave speed All waves travel at different speeds Use an equation to calculate wave speed w a v e l e n g t h (m) = w a v e s p e e d (m/s) w a v e p e r i o d (s) Wave Period Time between the passage of two wave crests (or troughs) at a fixed point

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25 Types of Waves Deep-water waves Shallow-water waves Move in water deeper than one half their wave-length When deep-water waves interact with ocean floor

26 Shore Currents Undertow When waves crash on the beach head on The water moved from this wave flows back into the ocean under the new incoming waves Movement of water from a shore current moving back into the ocean Pulls objects with the current

27 Longshore Currents Travel near or parallel to the shore line Form when waves hit the shore at an angle Transport most of the sediment in beach environments

28 Open-ocean waves Form in the open ocean 2 Types Whitecaps Swells Whitecaps White, foaming waves Very steep crests Break in the open ocean before reaching the shore

29 Swells Tsunami Rolling waves that move steadily across the ocean Form when a large volume of ocean water is suddenly moved up or down Caused by underwater earthquakes

30 Storm Surges Local rises in sea level near the shore that are caused by strong winds from a storm The storm blows water into a big pile under the storm As the storm moves onto shore, so does the giant mass of water beneath it

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32 Tides

33 Tide The Lure of the Moon Daily changes in the level of ocean water How often a tide occurs and the difference in tide levels depend on the position of the moon as it travels around Earth

34 High Tides When part of the ocean is facing the moon, the water there and on the opposite side of Earth bulges towards the moon Low Tides Water is taken from these areas to form high tides

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36 Timing of tides Occur at different times each day because Earth rotates quicker than the moon revolves around Earth

37 The Sun Tidal Variations Also effects tides Combination of sun and moon position in relation to Earth causes tidal ranges Tidal Range Differences in ocean levels at high and low tides

38 Spring Tide Neap Tide Largest daily tidal range Occur during full and new moons Sun, Moon, and Earth are aligned Smallest daily tidal range Occur during 1 st and 3 rd quarters of the moon Sun, Moon, and Earth form a 90 angle

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40 Tidal Bore Occurs in coastal areas with narrow inlets Body of water rushes up through a narrow bay, estuary, or river channel during the rise of a high tide Causes a very sudden tidal rise

41 What is Climate?

42 Weather daily conditions of the atmosphere temp, wind, precipitation, humidity vary day to day Climate average weather conditions in an area over time

43 Latitude distance north of south from equator Solar Energy energy from the sun hits most directly at the equator; most indirectly at the poles

44 Seasons seasons change due to the tilt of the Earth s axis tilt affects how much solar energy an area receives near equator and poles have little to no seasonal change

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46 Prevailing Winds Mountains winds that blow mainly from one direction affects precipitation in areas affects both temperature and precipitation of areas on either side of mountain

47 Large Bodies of water Ocean Currents affects an area s climate water absorbs and releases heat slower than land helps to moderate temp of land around it surface currents carry warm or cool water to coastal areas

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49 Climate Zones three major zones: tropical temperate polar Biome large zone characterized by climate, types of plants and animals

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51 Changes in Climate Ice Age long period of climate cooling ice covered large areas of land Volcanic Eruptions creates shield or dust and ash that block s sun s rays and cools climate

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53 Asteroid Impact acts like a volcano throws debris (dust) into air that blocks sun = cools climate Sun s Cycle sun follows 11- year cycle has periods of high and low radiation

54 Global Warming Greenhouse Effect gradual increase in average global temp natural process warming of planet due to gases in atmosphere essential for maintaining temp on surface

55 Greenhouse Effect human activities increase gases gases trap and hold more heat result: warmer planet and climate changes carbon dioxide: main contributor to climate change major greenhouse gases: carbon dioxide, water vapor, methane, nitrous oxide

56 Consequences of global warming positive impacts longer growing seasons more comfortable climates in cold areas fewer cold-related deaths

57 negative impacts rising sea levels (due to melting ice) causing loss of land more severe weather (hurricanes, tornados, floods, droughts) species extinction; species unable to adapt to climate changes