Subequatorial Belt

Subequatorial Belt 

one of the natural geographic belts of the earth in the northern and southern hemispheres. Situated between the equatorial and tropical belts, subequatorial belts are characterized by a seasonal shift of equatorial air masses in summer to tropical masses (trade winds) in winter. The equatorial monsoonal climate is evident in the rhvthmic seasonal alternation of dry and rainy seasons with characteristic natural processes. The average monthly temperature ranges from 15° to 32°C. Annual precipitation varies from 250 to 2,000 mm, with 90–95 percent falling during the rainy season that lasts between two to three and nine to ten months.

Landforms are divided into meridionally situated zones and comprise permanently humid forests, seasonally humid deciduous (monsoonal) forests, humid high-grass savannas and savanna forests, typical savannas, wasteland savannas, and thin forests. The mountains have forest-meadows in humid regions and forest-steppes in arid regions. The laterite soils range from podzolized laterites to red-brown savanna soils. The most typical fauna include ruminants, predators, rodents, and termites.

In the ocean the subequatorial belts are bounded by the Northern Trade Wind Current. The average water temperature is 25°C. Salinity decreases to 37 parts per thousand toward the equator. The weak vertical mixing of the water results in a deficiency of oxygen and a low plankton content (50–70 mg per cu m).

The landforms of the subequatorial belts have been greatly altered by man, especially in South and Southeast Asia. The land has been put to use for consumer and large-scale commercial farming and for grazing livestock, mainly cattle.

REFERENCES

Ivanov, N. P. Landshaftnoklimaticheskie zony zemnogo shara. Moscow-Leningrad, 1948.
Walter, H. Rastilel’nost’ zemnogo shara. Moscow, 1968. (Translated from German.)
Glazovskaia, M. A. Pochvy mira, parts 1–2. Moscow, 1972–73.
Kalesnik, S. V. Obshchie geograficheskie zakonomernosti Zemli. Moscow, 1970.
Riabchikov, A. M. Struktura i dinamika geosfery, ee estestvennoe razvitie i izmenenie chelovekom. Moscow, 1972.
Klimaty zarubezhnoi Azii. Leningrad, 1975.

L. I. KURAKOVA