Billede:Milankovitch Variations.png

[edit] Description

This figure shows the variations in Earth's orbit, the resulting changes in solar energy flux at high latitude, and the observed glacial cycles.

According to Milankovitch Theory, the precession of the equinoxes, variations in the tilt of the Earth's axis (obliquity) and changes in the eccentricity of the Earth's orbit are responsible for causing the observed 100 kyr cycle in ice ages by varying the amount of sunlight received by the Earth at different times and locations, particularly high northern latitude summer. These changes in the Earth's orbit are the predictable consequence of interactions between the Earth, it's moon, and the other planets.

The orbital data shown is from Quinn et al. (1991). Principal frequencies for each of the three kinds of variations are labeled. The solar forcing curve (aka "insolation") is derived from July 1st sunlight at 65 °N latitude according to Jonathan Levine's insolation calculator [1]. The glacial data is from Lisiecki and Raymo (2005) and gray bars indicate interglacial periods, defined here as deviations in the 5 kyr average of at least 0.8 standard deviations above the mean.

This image is intended to replace Image:Milankovitch_patterns.jpg.

[edit] Copyright

This image was produced by Robert A. Rohde from publicly available data, and is incorporated into the Global Warming Art project.

[edit] References

• Lisiecki, L. E., and M. E. Raymo (2005), A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records, Paleoceanography 20, PA1003, doi:10.1029/2004PA001071.[2]
• Quinn, T.R. et al. "A Three Million Year Integration of the Earth's Orbit." The Astronomical Journal 101 pp. 2287-2305 (June 1991).