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Chapter 2 Solar Energy to Earth and the Seasons. Robert W. Christopherson Charlie Thomsen. Solar Energy to Earth and the Seasons. The Solar System, Sun, and Earth Solar Energy: From Sun to Earth The Seasons . The Solar System, Sun, and Earth . Solar System formation and structure - PowerPoint PPT Presentation
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Chapter 2Solar Energy to
Earth and the Seasons
Robert W. ChristophersonCharlie Thomsen
Solar Energy to Earth and the Seasons
The Solar System, Sun, and Earth
Solar Energy: From Sun to Earth
The Seasons
The Solar System, Sun, and Earth
Solar System formation and structure Gravity
Planetesimal hypothesis
Dimensions and distancesSpeed of light
Earth’s orbit
Solar System Formation and Structure
GravityMutual attracting force exerted by mass on all other objects
Planetesimal hypothesisSuns condense from nebular clouds
Dimensions and DistancesSpeed of light
299,792 kmps (186,282 mps)
Milky Way Galaxy 100,000 ly across
Our Solar System 11 light-hours across
Moon is 1.28 light-seconds away
Milky Way Galaxy
Figure 2.1
Dimensions and DistancesEarth’s orbit
Average distance from Earth to the Sun is 150,000,000 km (93,000,000 mi)
Perihelion – closest at January 3147,255,000 km (91,500,000 mi)
Aphelion – farthest at July 4152,083,000 km (94,500,000 mi)
Earth is 8 minutes 20 seconds from the Sun
Plane of Earth’s orbit is the plane of the ecliptic
Our Solar System
Figure 2.1
Solar Energy: From Sun to Earth
Solar activity and solar wind
Electromagnetic spectrum of radiant energy
Intercepted energy at the top of the atmosphere
Solar Activity and Solar WindSolar wind is clouds of electrically charged particles
Sunspots are caused by magnetic storms
Sunspots have activity cycle of 11 years
Figure 2.2
Aurora Borealis
Figure 2.4
The Electromagnetic SpectrumSun radiates shortwave energy
Shorter wavelengths have higher energy
Earth radiates longwave energy
Wavelength and Frequency
Figure 2.5
The Electromagnetic Spectrum
Figure 2.6
Solar and Terrestrial Energy
Figure 2.7
Earth’s Energy Budget
Figure 2.8
Distribution of InsolationTropics receive more concentrated insolation due to Earth’s curvature
Tropics receive 2.5× more than poles
Figure 2.9
The Seasons Seasonality
Reasons for seasons
Annual march of the seasons
Insolation at Top of Atmosphere
Figure 2.10
SeasonalitySeasonal changes
Sun’s altitude – angle above horizon
Declination – location of the subsolar point
Daylength
Daily Net Radiation
Figure 2.11
Reasons for Seasons Revolution
Rotation
Tilt of Earth’s axis
Axial parallelism
Sphericity
Reasons for Seasons Revolution
Earth revolves around the Sun
Voyage takes one year
Earth’s speed is 107,280 kmph (66,660 mph)
RotationEarth rotates on its axis once every 24 hours
Rotational velocity at equator is 1674 kmph (1041 mph)
Revolution and Rotation
Figure 2.13
Reasons for Seasons Tilt of Earth’s axis
Axis is tilted 23.5° from plane of ecliptic
Axial parallelismAxis maintains alignment during orbit around the Sun
North pole points toward the North Star (Polaris)
Sphericity
Axial Tilt and Parallelism
Figure 2.14
Annual March of the SeasonsWinter solstice – December 21 or 22
Subsolar point Tropic of Capricorn
Spring equinox – March 20 or 21Subsolar point Equator
Summer solstice – June 20 or 21Subsolar point Tropic of Cancer
Fall equinox – September 22 or 23Subsolar point Equator
Annual March of the Seasons
Figure 2.15
11:30 P.M. in the Antarctic
Figure 2.16
Midnight Sun
Figure 2.17
Seasonal Observations
Figure 2.18
Robert W. ChristophersonCharlie Thomsen
Geosystems 7eAn Introduction to Physical Geography
End of Chapter 2
