Orbital Forcing of Climate
Wobbles in the Earth's orbit around the sun cause the intensity of sunshine to vary as a function of latitude and season. The Earth's axis of rotation tilts with varying obliquity on time scales of 40 kyr, the direction of the tilt rotates (precesses) on a cycle of about 20 kyr, and the eccentricity of the Earth's orbit around the sun varies with cycle times of 100 and 400 kyr.
Run the "snapshot" model to see the distribution of incoming solar energy with latitude and season for some year in the past or future, or invent your own orbital parameters. Or run the "time series" model to see the variation of solar intensity on a given day in the year, as a function of latitude and time in the past and future.