Rainfall and the tropical climate dominate the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year, roughly following the solar equator. The tropical rain belt is an area of active rain that is positioned mostly around the tropics.
Mechanism
The reason the rain belt is situated near the tropics can be attributed to the fact that the Sun's radiation is strongest near the equator, which is located in the middle of the tropics. This solar radiation generates large amounts of heat near the equator. This causes the air at ground level in the tropics to warm up. Because hot air is less dense than cold air, the hot air rises into the upper levels of the atmosphere, cooling as it rises.
The tropical rain belt lies in the Southern Hemisphere of the Indian Ocean and western Pacific Ocean roughly from October to March, and during this time the northern tropics experience a dry season in which precipitation is very rare, and days are typically hot and sunny throughout. From April to September, the rain belt lies in the Northern Hemisphere, and a wet season occurs there, while the southern tropics experience their dry season.
The rain belt reaches roughly as far north as the Tropic of Cancer and as far south as the Tropic of Capricorn in the western Pacific Ocean. Its variation in the Western Hemisphere is minimal, roughly between the equator and the 15th parallel north latitude. Near these latitudes, there is one wet season and one dry season annually. On the equator, there are two wet and two dry seasons as the rain belt passes over twice a year, one moving north and one moving south. Between the tropics and the equator, locations may experience both a short wet and a long wet season. Local geography may substantially modify these climate patterns.
thumb|alt=Map showing approximate location of tropical rain belt|Map showing approximate location of tropical rain belt
Effects of climate change
As the earth warms, the rain belt is projected to move north of the current position. Recent climate change can be attributed to rising carbon dioxide concentrations in the atmosphere; caused by the burning of fossil fuels. The correlation between the concentration of carbon dioxide in the atmosphere and average global temperature is undeniably direct, meaning that as more carbon dioxide is released into the atmosphere, the temperature of the Earth is expected to rise as well. Even though the Earth is warming as a whole entity, the Northern Hemisphere is warming faster than the Southern because of melting Arctic sea ice.
As the Northern Hemisphere warms, a temperature gradient is established between the Northern and Southern hemispheres.
Dargan Frierson explains that in this process, the Northern Hemisphere receives more heat than the Southern because the overturning circulation brings more heat into the Northern Hemisphere as opposed to the Southern. He also states that as a result, the extra heat is transferred to the tropical regions in the Northern Hemisphere, causing warm ocean water to be situated in the northern tropics.