The weather in the
tropicsThe tropics,the tropics are very hot. hi everyone! peace out!seated in the equatorial regions of the world, are limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' N latitude and the Tropic of Capricorn in the southern hemisphere at 23°26' S latitude...
is dominated by the
tropical rain belt, which oscillates from the northern to the southern tropics in the Eastern Hemisphere over the course of the year. The tropical rain belt lies in the southern hemisphere of the
Indian oceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering about 20% of the water on the Earth's surface. It is bounded on the north by South Asia ; on the west by Africa; on the east by Indochina, the Sunda Islands, and Australia; and on the south by the Southern Ocean...
and western
Pacific oceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and...
roughly from October to March, and during this time the northern tropics experience a
dry seasonThe dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
in which precipitation is very rare, and days are typically hot and sunny throughout.
The weather in the
tropicsThe tropics,the tropics are very hot. hi everyone! peace out!seated in the equatorial regions of the world, are limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' N latitude and the Tropic of Capricorn in the southern hemisphere at 23°26' S latitude...
is dominated by the
tropical rain belt, which oscillates from the northern to the southern tropics in the Eastern Hemisphere over the course of the year. The tropical rain belt lies in the southern hemisphere of the
Indian oceanThe Indian Ocean is the third largest of the world's oceanic divisions, covering about 20% of the water on the Earth's surface. It is bounded on the north by South Asia ; on the west by Africa; on the east by Indochina, the Sunda Islands, and Australia; and on the south by the Southern Ocean...
and western
Pacific oceanThe Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Tepre Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and...
roughly from October to March, and during this time the northern tropics experience a
dry seasonThe dry season is a term commonly used when describing the weather in the tropics. The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year...
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 seasonThe wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region falls. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics...
occurs there, while the southern tropics experience their dry season.
The rain belt reaches roughly as far north as the
Tropic of CancerThe Tropic of Cancer, or the Northern tropic, is one of five major degree measures or major circles of latitude that mark maps of the Earth. It is the northmost latitude at which the sun can appear directly overhead at noon...
and as far south as the
Tropic of CapricornThe Tropic of Capricorn, or Southern tropic, is one of the five major circles of latitude that mark maps of the Earth. It lies 23° 26′ 22″ south of the equator, and marks the most southerly latitude at which the sun can appear directly overhead at noon...
in the western Pacific ocean, although there have been in such cases where the rain belt itself has gone far into the temperate zones especially those near the
Tropic of CancerThe Tropic of Cancer, or the Northern tropic, is one of five major degree measures or major circles of latitude that mark maps of the Earth. It is the northmost latitude at which the sun can appear directly overhead at noon...
and the
Tropic of CapricornThe Tropic of Capricorn, or Southern tropic, is one of the five major circles of latitude that mark maps of the Earth. It lies 23° 26′ 22″ south of the equator, and marks the most southerly latitude at which the sun can appear directly overhead at noon...
. 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, once moving north and once moving south. Between the tropics and the equator, locations may experience a short wet and a long wet season. Local geography may substantially modify these climate patterns, however.
Relationship to global dimmingGlobal dimming is the gradual reduction in the amount of global direct irradiance at the Earth's surface that was observed for several decades after the start of systematic measurements in the 1950s. The effect varies by location, but worldwide it has been estimated to be of the order of a 4%...
The earth is hottest roughly where the sun shines most strongly. This occurs north or south of the equator depending on the season. The hot air rises and cools, causing tropical rainfall. The now-dry air then moves away from the equator and sinks, warming and dropping in relative humidity and creating an area of almost no rain. Where rain falls throughout the year there is tropical rain forest. Where rain falls almost never there is desert, for example the Sahara. Where rain falls only when the rainbelt is closest, there is a summer rainy season and a winter dry season, for example in the
SahelThe Sahel or Sahel Belt is a semi-arid tropical savanna and steppe ecoregion in Africa, which forms the transition between the Sahara to the north and the slightly less arid savanna belt to the south, known as the Sudan .-Geography:The Sahel runs 2,400...
.
There is significant evidence that human activities affect the position of the rain belt. Most particulate pollution is released in the northern hemisphere, and atmospheric mixing between the hemispheres is minor. This decreases the sunlight reaching the northern hemisphere, moving the belt of maximum sunlight southward. This may explain why in recent decades the Sahel has experienced record droughts. More recently, Western Europe and North America have made great efforts to reduce particulate emissions, while the ex-Soviet bloc may have also involuntarily reduced emissions. Thus the maximum sunlight belt has moved north again, bringing unexpected flooding to the Sahel and droughts to
ZimbabweZimbabwe , is a landlocked country located in the southern part of the continent of Africa, between the Zambezi and Limpopo rivers...
.