Components of the Climate System

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Components of the Climate System

• Atmosphere
• Ocean

• Biosphere
• Geosphere

Image from NASA
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Atmosphere Ocean Circulation

• Earth is unevenly heated
• This creates warmer, higher energy areas
• Fluids flow from higher to lower energy areas
  (you can think of this as being downhill
• H L

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Atmosphere Ocean Circulation

• Atmospheric Circulation
• Depends on density
• Ocean Surface Circulation
• Depends on the wind
• Deep Ocean Circulation
• Depends on density

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What Influences Global Atmospheric Circulation?

• 1) Uneven latitudinal solar heating (e.g. low vs.
  high latitude)
• which creates pressure differences
• 2) Rotation of the Earth (the "Coriolis Effect")
• 3) Land/sea temperature contrasts

NASA Image Dec. 7, 1972, Africa and Saudi
Arabia as viewed from Apollo 17 as it left earth
for the moon. it was the first time that the
trajectory of an Apollo mission enabled a view of
the south pole. http//nssdc.gsfc.nasa.gov/photo_
gallery/photogallery-earth.html
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Incoming Solar radiation at the bottom of the
Earths atmosphere uneven heating
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Suns radiation to Earth Unequal distribution
1) Footprint
At higher latitudes the solar radiation is
distributed over a larger area
Earth
Sun is about 150 x 106 km (93 x106 mi) from
Earth.)
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Suns radiation to Earth Unequal Distribution
2) Length of Path through Atmosphere
At higher latitudes the suns radiation travels
over a longer path in the earths atmosphere.
This increases the amount of atmospheric
interactions, the opportunities for reflection
absorption.
Earth
Atmosphere
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Suns radiation to Earth Unequal Distribution
3) Tilt of Earth unequal exposure to sun Tilt
of Earths axis causes seasons

• axis of earth tilted 23.5 degrees
• summer solstice - June 21 22 - axis tilted toward
  sun
• winter solstice - Dec 21,22 - axis tilted away
  from sun
• autumnal equinox - Sept 22,23 - rays vertical at
  equator
• vernal or spring equinox - March 21,22 rays
  vertical at equator

http//physics.uwstout.edu/wx/Notes/ch2notes.htm
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UNEQUAL HEATING OF EARTH
BUT Outgoing solar radiation is not as uneven
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Solar Radiation Heat Transport

• Look at the figure on left. What is happening?
• Tropics
• - gain more heat from the sun than they lose to
  space
• - heat surplus
• Poles
• - lose more heat to space than they gain from the
  sun
• - heat deficit
• What happens?
• Heat is transported from the tropics to the poles
  to even out the surplus and deficits

• Image Garrison, Fig. 8.4b, pg 189.

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Consider the Following

• How does water in a kettle heat up to a boil?
• Why is air in a room warmer near the ceiling than
  close to the floor?
• Why does smoke emerge from the factory stacks and
  rise up in the air?
• Why does lava ooze out of cracks in the ocean
  floor?
• How do clouds form?
• The answer to all of these is
• Convection.

Image from http//australiasevereweather.com/phot
ography/photos/1995/0205mb12.jpg
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Fluid Atmosphere

• The atmosphere is a three dimensional fluid.
• The air moves horizontally and vertically
  creating a mosaic of weather phenomena, and
  shaping the properties of climate.

NASA Image Hurricane Floyd -1999
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Motion of Air

• Two columns of air with the same number of
  molecules.

• Right column heats and expands, left column is
  relatively cooler.

• Air pressure along the dotted line is higher
  in the right column above the line.

• Air will flow from the right (red) column to
  the left column.

• This increases the pressure in the left column
  and the air flow from left to right.

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Vertical Motion of Moist Air

• As an air parcel rises
• - it expands
• - it cools
• - water vapor can condense from the cooler air
  forming clouds
• Ascending air expands, cools and moistens
• Descending air compresses, warms and dries out
• Image Garrison, Fig. 8.1a, pg 187.

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Simplified atmospheric convection cell on a
non-rotating Earth

• Warm air rises in the tropics.
• Cool air sinks at the poles.
• Horizontal currents close the loop.
• Flow to north aloft
• Flow to south at the surface
• Net Result heat is transported from the tropics
  to the poles.

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Circulation gtWeather -- Troposphere
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Earth Rotation and Atmospheric Circulation

Low pressure areas (red arrows) are created when
warm air rises

• Image (left) Garrison, Fig. 8.7, pg 190, (right)
  Garrison Fig. 8.12, pg 193.

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Coriolis Effect
Coriolis Force
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Coriolis Effect - Force
Objects traveling appear to be deflected because
of the earths rotation. In the Northern
Hemisphere objects appear to move to the right of
the direction in which they travel. In the
Southern Hemisphere objects appear to move to the
left of the direction in which they travel.
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Coriolis Effect/Force

• Coriolis Effect/Force Depends upon
• Latitude,
• 0 _at_ equator,
• greatest at poles
• Speed at which object is moving

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Rotation of a Sphere (Earth) Results in the
Coriolis Effect

• The linear distance travelled by a point on the
  Earth's surface depends on latitude
• Objects at the equator travel farther in one day
  than objects at other latitudes
• The difference in linear speed with latitudes
  produces the "Coriolis effect"

Image Graphic Garrison, Fig. 8.8, pg 189.
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Coriolis Effect

• In 1 hour Buffalo and Quito both move 15 degree
• Buffalo moves 787 mi
• Quito moves 1,036 mi

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Coriolis Effect
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Coriolis

• The orange arrow represents some object sent
  north from the equator. By the time it reaches
  the labeled northern latitude, it's gone farther
  east than a point on the ground would have, since
  it kept its eastward speed from where it started.
  
• Similarly, the yellow arrow started away from the
  equator at a slower eastward speed, and doesn't
  go as far to the east as the ground at the
  equator ... seeming to deflect west from the
  point of view of the ground.

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Motion of Air or Water
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High and Low Fluid Pressure

• The higher water or air level creates higher
  fluid pressure at the bottom of tank A and a net
  force directed toward the lower fluid pressure at
  the bottom of tank.
• This net force causes water or air to move from
  higher pressure toward lower pressure.

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Fluids Flow - From High to Low Pressure
100 km
1012 mb
1006 mb
Pressure Gradient Force 6 mb/ 100 km
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Fluid Flow - From High to Low Pressure
Deflected to the Right in the Northern Hemisphere
by the Coriolis Force/Effect
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Fluid Flow - From High to Low Pressure
Deflected to the Right in the Northern Hemisphere
by the Coriolis Force/Effect Actual path is in
between the two forces
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Words into Action

• http//www.eoascientific.com/interactive/the_corio
  lis_effect/the_coriolis_effect.html

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Atmospheric Circulation

• Where are the low Pressure areas?
• ITCZ would be one area (flowing to low pressure

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Atmospheric Circulation
Where does the location of the ITZ change the
most?