The Movement of Ocean Water

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The Movement of Ocean Water

• Currents

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• Ocean Current

• movement of ocean water that follows a regular
  pattern
• influenced by
• weather
• Earths rotation
• position of continents

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• Surface current

• horizontal movement of ocean water caused by wind
• occurs at or near oceans surface
• controlled by
• global winds
• Coriolis effect
• continental deflections

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• Global Winds

• winds that blow across Earths surface that
  create surface currents
• different winds cause currents to flow in
  different directions

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• Coriolis Effect

• Earths rotation causes wind and surface currents
  to move in a curved path

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• Continental Deflections

• when surface currents meet continents, the
  currents deflect (change direction)

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• 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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• 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

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• Increasing Density
• Increasing Salinity (Freezing)

• cold air chills water, increases density, cold
  water sinks
• when water freezes, salt gets squeezed out at
  surface and enters liquid below
• increases density

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• Increasing Salinity (Evaporation)

• warm climates, water evaporates, leaves salt
  behind
• increases density, sinks to form deep current

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Currents and Climate
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Surface Currents

• Warm-Water

• Currents that create warm climates in coastal
  areas that would otherwise be much cooler

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• Cold-Water

• Keep coastal areas cooler than inland climate

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• 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

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• 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

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• Studying El Niño
• 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

La Niña
El Niño
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Waves
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Anatomy of a Wave

• Wave
• Crest
• Trough

• Made up of crests and troughs
• Highest point of a wave
• Lowest point of a wave

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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

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Specifics of Wave Movement

• Wave speed
• Wave Period

• All waves travel at different speeds
• Use an equation to calculate wave speed
• Time between the passage of two wave crests (or
  troughs) at a fixed point

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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

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• 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

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• 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

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• Open-ocean waves
• Whitecaps

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

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• 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

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• 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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Tides
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The Lure of the Moon

• Tide

• 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

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• High Tides
• Low Tides

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

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• Timing of tides

• Occur at different times each day because Earth
  rotates quicker than the moon revolves around
  Earth

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Tidal Variations

• The Sun
• Tidal Range

• Also effects tides
• Combination of sun and moon position in relation
  to Earth causes tidal ranges
• Differences in ocean levels at high and low tides

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• 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 1st and 3rd quarters of the moon
• Sun, Moon, and Earth form a 90 angle

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• 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

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What is Climate?
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• Weather
• Climate

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

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• Latitude
• Solar Energy

• distance north of south from equator
• energy from the sun
• hits most directly at the equator most
  indirectly at the poles

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• Seasons

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

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• 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

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• Large Bodies of water
• Ocean Currents

• affects an areas 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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• Climate Zones
• Biome

• three major zones
• tropical
• temperate
• polar
• large zone characterized by climate, types of
  plants and animals

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Changes in Climate

• Ice Age
• Volcanic Eruptions

• long period of climate cooling
• ice covered large areas of land
• creates shield or dust and ash that blocks suns
  rays and cools climate

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• Asteroid Impact
• Suns Cycle

• acts like a volcanothrows debris (dust) into air
  that blocks sun cools climate
• sun follows 11-year cycle
• has periods of high and low radiation

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• 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

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• 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

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• Consequences of global warming
• positive impacts

• longer growing seasons
• more comfortable climates in cold areas
• fewer cold-related deaths

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• 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