Atmospheric circulation during warm geologic periods: Is the equator-to-pole surface-temperature gradient the controlling factor?

Paleoclimatologists have hypothesized that the equator-to-pole surface-temperature gradient is a dominant control on the paleocirculation of the oceans and the atmosphere. Atmospheric simulations using realistic Cretaceous (100 m.y. ago) geography are used to examine quantitatively the relationships between paleogeography, surface-temperature gradients, and the nature of the atmospheric circulation. These results raise questions concerning the classical theories and interpretations of warm paleoclimates and suggest that paleogeography is an important factor governing the nature of the circulation.