Within the Tropics there are different
vegetation zones. These depend on the time, during which there is sufficient water available for plants to grow. The differentiation is made according to number of dry (
arid*) and wet (
humid*) months:
The
humid climate close to the equator changes to a
semi-humid bzw.
semi-arid tropical climate towards the
Tropics*) , which results in different
ecozones*) from
tropical forests*) over various types of
Savanna*) to the tropical semi-deserts and
deserts zeigt.
In the
humid tropics, which surround the equator with exception of East Africa and the Andes,
tropical rain forests form. The
semi-humid tropics, in which the
dry-*) and
wet seasons*) shape the
seasons, are characterised by
Savannas*) ,
Dry forests*) and
Monsun forestsr*) , which flank the
tropical rain forests, and also the wetlands of the
Pantanal*) in South America belong to this zone. The
arid tropics are
deserts and
semi-deserts, where only small changes of temperature occur in the course of the year.
The tropical zone (v. gr.:
tropai heliou sun turning areas) is the warmest
climate zone of the earth. The Tropics are:
- radiation-climatically regards the areas, which are limited by the Tropic of cancer and the tropic of capricorn (23,5° northern and southern latitude) and in those the sun stands at least once the year in the zenith (highest conditions = 90°C to the ground).
- in the system of the atmospheric circulation the range between the two subtropical-edge-tropical high pressure belts of the north and Southern Hemisphere of the earth.
- the range on both sides the equator, is coined/shaped by higher dailytemporal (time of day climate) and smaller seasonal variations in temperature (25 °C annual averages), since by the all year round high irradiation no thermal seasons can form,
- the range, within which the daily lengths in the course of the yearly vary only slightly between 10,5 and 13,5 hours.
As a border of the Tropics to the subtropics "Köppen" used the 18°-Isotherme, Supan and Phlippson the 20°-Isotherme of the coldest month. These demarcations refer however only to the warm tropics lain in small height over the sea level. In addition, the typical climatic characteristics of the Tropics are valid for the areas lain more highly. Because of the temperature decrease with the height one speaks if the 18° or 20°-Isotherme is fallen below, but computationally a higher value would result, from the cold tropics.
Ektropen are areas, which are not in the tropics.