Why are most deserts at 30° North or South and tropical rainforests are near or at the equator?
- Warm air rises in equatorial regions, which absorbs water readily
- Adiabatic cooling of the air mass occurs as it rises; cooler air holds less water, causing rain in the tropics
- Rain results in dry air as the air mass descends at 30° North or South
- Furthermore, adiabatic warming of the air mass warms the air and holds more water