Review Question

1
Review Question

• In your own words, define Geography.
• BAD Answer
• The science that studies the relationships
  between natural and cultural systems and the
  interdependence of the two over space and time
• These are not YOUR words!

2
Review Question

• Sunspots
• A) Are produced by coronal mass ejections
• B) Are caused by solar wind
• C) Have activity cycles
• D) Are clouds of electrically charged particles

3
Review Question

• According to Weins Law
• A) The electromagnetic spectrum divides radiant
  energy
• B) Longer wavelengths have higher energy
• C) Shorter wavelengths have high energy
• D) The Earth is an open system in terms of energy

4
Review Question

• Solar rays pass through more atmosphere before
  reaching the poles, so more energy is lost to
  ____________, ______________, and
  _______________.
• Absorption, scattering, and reflection

5
Chapter 2Solar Energy to Earth and the Seasons

• Geosystems 6e
• An Introduction to Physical Geography

Robert W. Christopherson Charles E. Thomsen
6
Perihelion and Aphelion
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The Seasons  

• Seasonality the variation of the suns position
  over the horizon the changing daylength during
  the year  
• Seasons result from
• variations in the suns altitude angle between
  the horizon and the sun
• the sunss declination latitude of the subsolar
  point
• and daylength - duration of exposure to
  insolation 

8
Reasons for Seasons 

• Revolution
• Rotation
• Tilt of Earths axis
• Axial parallelism
• Sphericity

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Reasons for Seasons 

• Revolution
• Earth revolves around the Sun
• Voyage takes one year
• Earths speed is 107,280 kmph (66,660 mph)
• Rotation
• Earth rotates on its axis once every 24 hours
• Rotational velocity at equator is 1674 kmph (1041
  mph)

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Revolution and Rotation
Figure 2.13
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Reasons for Seasons 

• Tilt of Earths axis
• Axis is tilted 23.5 from plane of ecliptic
• Axial parallelism
• Axis maintains alignment during orbit around the
  Sun
• North pole points toward the North Star (Polaris)
• Sphericity

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Axial Tilt and Parallelism
Figure 2.14
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Seasonal Observations
Figure 2.17
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Seasonal Observations
SUMMER HEMISPHERE Carrollton 33N What is Suns
angle (at noon) on June 21? 90 (latitude
subsolar point) 90 (33 23.5) 80.5
WINTER HEMISPHERE 90 (latitude subsolar
point) What is the Suns angle (at noon) on
Dec 21? 90 (33 23.5) 33.5
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Seasonal Observations

• What is the noon altitude of the sun at
  Carrollton at the equinoxes?
• Use either summer or winter hemisphere equation
• 90 (latitude subsolar point)
• 90 (33 0) 57

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Annual March of the Seasons

• Winter solstice December 21 or 22
• Subsolar point Tropic of Capricorn
• Spring equinox March 20 or 21
• Subsolar point Equator
• Summer solstice June 20 or 21
• Subsolar point Tropic of Cancer
• Fall equinox September 22 or 23
• Subsolar point Equator

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Annual March of the Seasons
Figure 2.15
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End of Chapter 2

• Geosystems 6e
• An Introduction to Physical Geography

Robert W. Christopherson Charles E. Thomsen