GEOG 102 Chapter 13: TropicalClimatologyTextbookChapter13
Document Summary
The episodic nature of the earth"s glacial and interglacial periods within the present ice. These glacial/interglacial periods have been caused by three cyclical changes in the earth"s circumnavigation around the sun. What do these cycles do: shape of earth"s orbit or eccentricity. Earth encounters more variation in energy (sunlight) that it receives when its" orbit is elongated than it does when earth"s orbit is more circular. Orbital shape ranges between more or less elliptical (0-5% ellipticity) on a cycle of about 100k years: tilt of earth"s axis or obliquity. energy the poles receive. Tilt of earth"s axis varies b/w 22. 2 - 24. 5 degrees. Gradual wobble affects earth"s relationship b/w its tilt and eccentricity. Together variations in these 3 cycles create alterations in seasonality of solar radiation received at earth"s surface. These increased or decreased radiation directly influence the earth"s climate system, thus influencing the advancement and retreat of earth"s glaciers.