Insolation Insolation = Incoming Solar Radiation Energy in = Energy out or, Insolation In = Heat Out (Earth only emits heat)
Factors Angle of insolation - direct or indirect Length of Day - how much sunshine is available. Type of Surface: -- light or dark -- rough or smooth
Angle of Insolation
Angle of Insolation
Axis Tilted Earth’s axis tilts 23.50 Always tilts the same way = parallelism Seasons result.
Parallelism
Seasons
Equinox Equinox = when the sun is directly over the equator. Day and night are equal = 12 hours long Sun rises due East, sets due West Vernal (spring) Equinox = March 20 Autumnal (fall) Equinox = Sept. 22
Solstice Solstice = sun stop Summer Solstice ( 6/21) = Sun is directly over 23.50 N (Tropic of Cancer) = most daylight Winter Solstice (12/21) = Sun is directly over 23.50 S (Tropic of Capricorn) = least daylight
Rotation Daily Motion = stars and planets rise in the East and set in the West. Why? Earth rotates counterclockwise at 15o / hr. Evidence: - Foucault’s Pendulum - Coriolis Effect – all winds move rightward in the northern hemisphere
Length of Day How long is a day? Is it 24 hours or 23 hrs. 56 minutes? Sidereal Day = actual time it takes to rotate 3600 (23h 56m). But, earth revolves around sun 10 in a day. So, it takes an additional 4 minutes to complete turn. Solar Day = Noon to Noon = Time it takes to rotate 3610 (24h).
Revolution Earth revolves around Sun 1o / day. Also counterclockwise. Evidence: Seasons. Constellations change during year.