1. n. [Reservoir Characterization]
The periodicities in the behavior of the Earth and its climate with respect to the sun. Some rhythms are caused by variations in the elliptically of the Earth's orbit, rotation of the semimajor axis of the Earth's orbit, variation on the tilt of the Earth's axis and rotation in the tilt of the Earth's axis. Most of these rhythms are predictable over the short term (up to hundreds of millions of years) but can become chaotic due to the influence of other planets (particularly massive Jupiter) or extra solar-system activity. The rhythms affect sea level and other factors that dictate the long-term behavior of depositional systems.