Geography 1400F/G Study Guide - Midterm Guide: Equinox, Pastoralism, Soil Retrogression And Degradation
24 Oct 2013
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<200,000 years ago: water cycle, oceans (marine life, oxygen, ozone layer, land life evolves, modern humans. People migrated and became isolated when glacial melted! Average global surface temperature varied by +/- 20 c. Age of the dinosaurs had no ice. The key to life on earth is water condensing to liquid. During the last glacial max 20,000 yrs ago, land bridges were formed as sea levels dropped by hundreds of meters. Isolation changes with season & latitude due to earth"s curvature, tilt and orbit. Most intense area of isolation pattern: vernal (spring) equinox 0 , summer solstice 23. 5 north, autumn equinox 0 , winter solstice 23. 5 south. Energy returns back to space as infrared radiation, some trapped by ghgs in troposphere. This varies due to the angle between earth and sun. Perpendicular angle 90 = more concentrated energy from sun: steady troposphere airflow from tropics to pole, creating wind circulation, surface ocean, top 200 m circulates.
