Physical Geography: GEOG 1301

Physical Geography: GEOG 1301

Spring 2005

Chapter Two: Solar Energy to Earth and the Seasons

Important Concepts:

Gravity- mutually attracting force- key force in the development of the universe and solar systems

Speed of light- 186,000 mps (6 trillion miles in one year)

Milky Way Galaxy- 100,000 lights years from edge to edge

Perihelion- earth closest to sun, around January 3

Aphelion- earth farthest from sun, around July 4

Sun- captured 99.9 % of matter from original solar system nebula

Solar Wind- stream of energetic material surging from sun (slower than light)

Sunspots- caused by magnetic storms on sun surface, produces flares on a regular cycle.

Solar wind effects- earth’s magnetosphere deflects solar wind (creates auroras at poles.)

§ Describe the Milky Way Galaxy and the Location of Earth

Go on a planet quest with NASA:

http://planetquest.jpl.nasa.gov/trip_planner_launch.html

http://planetquest1.jpl.nasa.gov/atlas/atlas_index.cfm

Windows to the Universe- interesting site:

http://www.windows.ucar.edu/

Good overview of the solar system and galaxies:

http://www.solarviews.com/eng/solarsys.htm#sun

StarDate from PBS!!!

http://stardate.org/resources/ssguide/

§ Describe, Insolation and its Importance

Electromagnetic Spectrum- radiant energy of various wavelengths. Solar radiation is a portion of this. Objects radiate energy in wavelengths related to surface temperature (hotter is a shorter wavelength.)

Insolation- “incoming solar radiation” Solar radiation that reaches a horizontal plane at earth. Radiation that arrives at Earth’s atmosphere and surface.

Thermopause- outer boundary of Earth’s energy system. Top of the atmosphere- 300 miles.

Solar constant- average insolation received at the thermopause (when earth is at its average distance from the sun.)

Subsolar point- place where radiant energy (insolation) strikes surface at a perpendicular angle.

Understand insolation receipts shown in figure 2.9 on page 50

Difference in angle of solar rays at varying latitudes creates uneven heating and distribution of insolation. Since radiation at poles passes through more atmosphere there is a greater loss of energy. (equator receives 2.5 more insolation than poles)

Insolation maps:

http://homer.ssec.wisc.edu/~insol/

Basic geometry of insolation

http://education.gsfc.nasa.gov/experimental/July61999siteupdate/inv99Project.Site/Pages/solar.insolation.html

§ Electromagnetic Energy (various wavelengths): Key essential solar input to life

http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html

· What effects net radiation patterns (page 52)?

Figure 2.11 on page 52

Insolation is shortwave, reflected, emitted radiation is longwave equals energy inputs minus energy outputs and gives global net radiation.

Earth loses more energy at the poles (negative energy)

Earth is a giant heat engine via atmosphere and oceans.