08-08-2014, 01:53 PM
Near-zero obliquity (axial tilt) would reduce the size of the polar regions (and the temperature gradients due to seasons). The obliquity sets the extent of the Arctic and Antarctic Circles.
Placement of deserts depends on atmospheric circulation and topography (mountain ranges forcing moisture in prevailing air currents to condense on the windward side before reaching the leeward side). Cold oceanic currents that inhibit the moisture content of the overlying atmosphere can produce deserts as well (e.g. the Atacama, Namib, and Kalahari Deserts). One way to produce widespread equatorial deserts is to ensure that the equatorial regions are covered by land that is distant from an ocean (where the oceans cross the equator, tall mountain ranges near the western coasts to force condensation into narrow coastal regions should suffice).
Radtech497
Placement of deserts depends on atmospheric circulation and topography (mountain ranges forcing moisture in prevailing air currents to condense on the windward side before reaching the leeward side). Cold oceanic currents that inhibit the moisture content of the overlying atmosphere can produce deserts as well (e.g. the Atacama, Namib, and Kalahari Deserts). One way to produce widespread equatorial deserts is to ensure that the equatorial regions are covered by land that is distant from an ocean (where the oceans cross the equator, tall mountain ranges near the western coasts to force condensation into narrow coastal regions should suffice).
Radtech497
"I'd much rather see you on my side, than scattered into... atoms." Ming the Merciless, Ruler of the Universe