Hot Wet Equatorial Climate

THE HOT, WET EQUATORIAL CLIMATE Distribution -Is found between 5° and 10°N and S of the equator. Its greatest extent is found in the lowlands of the Amazon, Congo D. R, Malaysia and the East Indies. -Further away from the equator, the influence on the on-shore Trade Winds gives rise to a modified type of equatorial climate with the Monsoon influences. -Within the tropics, the equatorial highlands have a distinctively cooler climate, modified by altitude such as the Cameron highlands, northern Andes and Kenyan highlands in East Africa

Map CLIMATE 1. Temperature – The most outstanding feature of an equatorial climate is its great uniformity of temperature through out the year – The mean annual temperatures are always around 27°C with very little variation. -there is no winter. -cloudiness and precipitation help to moderate the daily temperature so that even at the equator itself the climate is bearable. -regular land and sea breezes also assist in maintaining a truly equable climate. -the diurnal range is small and so is the annual range.

Figures below illustrate the rhythm of climate experienced in two different equatorial regions, one on lowland (Kuala Lumpur) and the other on the highland (Bogota). Kuala Lumpur Month JFMAMJJASOND Temp(°C)262627272727262626262627 Rainfall (mm)170170236279216127104157185274257231 Annual precipitation 2 413mm Annual temperature range 1°C (27°C – 26°C) Bogota Month JFMAMJJASOND Temp(°C)141415151414141414141414 Rainfall (mm)948912424416581668474213224142 Annual precipitation 1 610mm Annual temperature range 1°C (15°C – 14°C) 2. Rainfall – Rainfall is heavy, between 1 524mm and 2 540mm and well distributed throughout the year. There is no month without rain. There are two periods of maximum rainfall, April and October which occur shortly after the equinoxes. The double rainfall peaks coinciding with the equinoxes are a characteristic feature of equatorial climates not found in any other type of climate. -Due to great heat in the equatorial belt mornings are bright and sunny. There is much evaporation and convection air currents are set up, followed by heavy downpours of convectional rains in the afternoon from the towering cumulonimbus clouds. -Besides the convectional rainfall, mountainous regions also experience much Orographic or relief rainfall.

In addition, there are some intermittent showers from cyclonic atmospheric disturbances caused by the convergence of air currents in the doldrums. -The relative humidity is constantly high (over80%) making one feel sticky and uncomfortable. NATURAL VEGETATION -Equatorial region support a luxuriant type of dense vegetation –the tropical rain forest- because of heavy rainfall and uniform temperature. -In the Amazon lowlands, the forest is so dense and so complete that a special term ‘Selvas’ is used. 1. A great variety of vegetation -The equatorial vegetation comprises a multitude of evergreen trees that yield tropical hardwood e. . mahogany, ebony, greenheart, cabinet woods and dyewoods. -There are smaller palm trees, climbing plants like lianas or rattan which may be hundred of metres long and epiphytic and parasitic plants that live on other plants. -Under the trees grow a wide variety of creepers, ferns, orchids and lalang 2. A distinct layer arrangement .-From the air, the tropical rain forest appears like a thick canopy of foliage. All plants struggle upwards for sunlight resulting in a peculiar later arrangement. -The tallest trees attain a height of 45m with dense undergrowth that can tolerate shade. 3. Multiple species Trees of equatorial rainforest are not found in pure stands of a single species like in the temperate where forests where only a few species occur in a particular area. This has made timber exploitation to be difficult. 4. Forest clearings -Many parts of the virgin tropical rainforests have been cleared either for lumbering or shifting cultivation. When these clearings are abandoned, less luxuriant secondary forests, called belukar in Malaysia, spring up. -These are characterised by short trees and very dense undergrowth. Mangrove forests thrive in the coastal areas and brackish swamps. LIFE AND DEVELOPMENT

The equatorial regions are generally sparsely populated. In the forests most primitive people live as hunters and collectors and the more advanced ones practice shifting cultivation. Food is so abundant in such a habitat that many people worry very little the life of the next day. There are numerous animals, birds and reptiles and can be hunted to serve the needs of the community. Crops grown include manioc (tapioca), yams, maize, bananas and groundnuts. Plantation agriculture is also practised widely with the outstanding crop, rubber. Malaysia and Indonesia are the leading producers of rubber.

Another tropical crop is cocoa, which is more extensively cultivated in West Africa in Ghana and Ivory Coast. Other crops include oil palm, cocoanuts, coffee, tea, tobacco, spices, bananas, pineapples, etc. FACTORS AFFECTING DEVELOPMENT •Equatorial climate and health: excessive heat and humidity expose human beings to sunstroke and to such diseases as malaria and yellow fever. •Prevalence of bacteria and insect pests. •Jungle hinders development and maintenance. •Rapid deterioration of tropical soil. •Difficulties in lumbering and live stock farming. •Poor pasture.