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Unformatted text preview: 11-13I.Seasonsa.Earth’s tilt causes seasons; summer (in north), northern hemisphere tilted toward sunb.Solstice – longest, shortest dayc.Equinox – 12 hrs day, 12 hrs nighti.Longyearbyen, Norway; northern-most town, daylight can change 45 minutes/dayii.Singapore on equator, daylight changes – secondsI I. Sun intensity – latitudinal variation in sunlight intensity – due to earth’s shapea.Equator – sunlight hits earth perpendicularly – most energy per unit areab.Poles – sunlight hits earth at oblique angle – energy diffusec.Same # hours light / different amounts heatd.Net movement of energy from equator to poles i.Global air circulationii.Ocean currentse.Warm air rises, air cools as rises from earth, cooler air fallsf.Warm air holds more moisture than cool, when air cools – condensation happens – clouds, precipitationI I I.Air circulation patternsa.Hadley cellsi.High temperatures in tropics- evaporation ii.Warm, wet air rises, cools, rains in tropicsiii. Dry air pushed toward polesiii....
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- Fall '08
- Plankton, Pacific Ocean, primary production, photic zone