Life on an Ocean Planet

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  the section heading.
• The Solar Connection
• The Coriolis Effect
• The Winds

Chapter Topic Menu
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• Life gets almost all its energy from the sun.
  Solar energy does more than provide energy for
  life on Earth it drives the wind and it drives
  the currents in the ocean. Earths temperature
  relies on sunlight. Therefore, the sun not only
  provides life, but also the conditions in which
  life exists.
• Air and Sun
• Air is a mixture of gases that surround us.
• The four layers of the atmosphere include
• 1. Troposphere the lowest layer. This one
  concerns us most.
• 2. Stratosphere
• 3. Mesosphere
• 4. Thermosphere the top layer which goes out
  into space.

The Solar Connection
Chapter 8 Pages 8-3 to 8-5
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Air and Sun (continued)

• The amount of water vapor in the air relates to
  air temperature, density,and pressure.
• As temperature rises, air pressure increases,
  and density decreases.
• Adding water vapor decreases the density even
  more.
• Warm air is less dense than cool air.
• When a saturated or nearly saturated air mass
  cools, it has more water vapor in it than it can
  hold. The vapor condenses, forming rain when the
  temperature is above freezing or snow when
  temperature is below freezing.
• Understanding air masses and the weather they
  create is important because
• 1. These movements redistribute heat around the
  Earth.
• 2. Precipitation is the primary source of fresh
  water.

The Solar Connection
Chapter 8 Pages 8-6 8-7
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The Earths Heat Balance

• About 50 of all the sunlight that reaches the
  atmosphere makes it to Earths surface.
• To maintain balance with the heat from the sun,
  all the energy absorbed reradiates through
  various paths back into space as infrared
  radiation.
• If this process were imbalanced with more heat
  coming in than leaving, the Earth would grow
  hotter and hotter until life perished.
• Uneven Heating
• Factors that cause the Earth to heat unevenly
• The Earth is round, the Earths axis is tilted,
  and the Earths orbit is elliptical hence the
  distance between the Earth and sun varies with
  time of year.
• Uneven heating causes weather in part due to
  convection.
• Convection is vertical circular currents caused
  by temperature differences in a fluidsuch as
  air. Warm air becomes less dense and rises. Cool
  dense air comes in to replaceit, which in turn
  warms and rises. This creates a circular airflow
  pattern.

The Solar Connection
Chapter 8 Pages 8-8 to 8-14
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Deflection to the Right or Left

• The Coriolis effect is the tendency for the path
  of a moving object to deflect to the right in the
  Northern Hemisphere and to deflect to the left in
  theSouthern Hemisphere.
• The Earths Rotation
• The Coriolis effect is caused by the
  Earthsrotation relative to an object in
  motionover its surface.
• Motion or lack of motion is relative to the
  placefrom which you observe it.
• Standing on the equator relative to anyone on the
  Earth, youre motionless.
• Someone at a fixed point in space would say
  youre moving. To that person, you are moving
  because the Earth is rotating.
• Major Ocean Gyres The Coriolis effect creates
  circular airflow and current patterns such as the
  major ocean gyres in the Northern Hemisphere to
  the right and in the Southern Hemisphere to the
  left.

The Coriolis Effect
Chapter 8 Pages 8-15 to 8-19
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The Coriolis Effect and the Wind

• The Coriolis effect deflects the air to the right
  in the Northern Hemisphere. This gives the air a
  circular flow pattern rather than a straight
  north-south pattern.
• Atmospheric circulation cells are six distinct
  air masses (three in each hemisphere) with
  individual air flow patterns.
• Of the six cells, the most important are the
  Hadley cells. These lie between the equator and
  approximately30 north or south latitude.
• Trade winds are caused by air rising at the
  equatorand moving northward. The air becomes
  denseenough from cooling and moisture loss to
  sink. Mostof the air descends and flows back
  toward theequator, deflecting westward as it
  flows.
• Between 30 and 60 latitude are the Ferrel
  cells. Theyexist because some of the wind that
  descends fromthe Hadley cells doesnt turn
  toward the equator.Instead it continues on
  toward the poles shifting to the right (Northern
  Hemisphere) as it moves. This is what causes the
  Westerlies, getting this name because theyre
  from the west.

The Winds
Chapter 8 Pages 8-20 8-21
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Intertropical Convergence Zones (ITCZ)

• The geographic equator is 0 latitude.
• The meteorological (ITCZ) equator is animaginary
  line marking the temperatureequilibrium between
  the hemispheres that shiftsnorth and south of
  the geographic equator withseasonal changes.
• The ITCZ equator is important becauseatmospheric
  and ocean circulation are approximately
  symmetrical on either side ofit not at the
  geographic equator.
• The Earths major deserts are found at
  30latitude. Here the downward vertical airflow
  brings dry air to the Earths surface.This leads
  to areas with little rainfall andsignificant
  evaporation.
• Where oceans/seas are alongside deserts, the
  combination of high evaporation and low rainfall
  makes the salinity of these waters higher than
  average.

The Winds
Chapter 8 Pages 8-22 8-23
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Monsoons and Cyclones

• Monsoons are seasonal wind pattern changes caused
  by heating or cooling on the continents. Monsoons
  cause summers with significant rainfall and
  winters with very little.
• Cyclones are large rotating storm systems of low
  pressureair with converging winds at the center.
  There are two maintypes extratropical and
  tropical.
• Extratropical cyclones occur where the Polar and
  Ferrelcells meet.
• Tropical cyclones form within a single
  atmospheric cell.
• In both cases, cyclones form when moist wind gets
  drawninto a low-pressure area, causing it to
  twist around on itself.
• Cyclones appear to rotate the wrong way with
  respectto the Coriolis effect.
• When a cyclone forms, the low pressure pulling
  the windinto the pattern is stronger than the
  Coriolis effect.
• The winds that get drawn in and provide the
  cyclone energy are pulled away from the Coriolis
  effect. This imparts the backwards spin.
• Cyclones help with the redistribution of heat
  that is important to all life on Earth.

The Winds
Chapter 8 Pages 8-23 to 8-25