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tropics,also called tropical zone or torrid zone, all the land and water of the earth situated between the Tropic of CancerTropic of Cancer,
parallel of latitude at 23°30' north of the equator; it is the northern boundary of the tropics. This parallel marks the farthest point north at which the sun can be seen directly overhead at noon; north of the parallel the sun appears less than 90°
..... Click the link for more information. at lat. 23 1-2°N and the Tropic of CapricornTropic of Capricorn,
parallel of latitude at 23°30' south of the equator; it is the southern boundary of the tropics. This parallel marks the farthest point south at which the sun can be seen directly overhead at noon; south of the parallel the sun appears less than 90°
..... Click the link for more information. at lat. 23 1-2°S. Every point within the tropics receives the perpendicular rays of the sun at noon on at least one day of the year. The sun is directly overhead at lat. 23 1-2°N on June 21 or 22, the summer solstice, and at lat. 23 1-2°S on Dec. 21 or 22, the winter solstice. Since the entire tropical zone receives the rays of the sun more directly than areas in higher latitudes, the average annual temperature of the tropics is higher and the seasonal change of temperature is less than in other zones. The seasons in the tropics are not marked by temperature but by the combination of trade winds taking water from the oceans and creating seasonal rains called monsoons over the eastern coasts. Several different climatic types can be distinguished within the tropical belt, since latitude is only one of the many factors determining climate in the tropics. Distance from the ocean, prevailing wind conditions, and elevation are all contributing elements. The tropics contain the world's largest regions of tropical rain-forest climate (Amazon and Congo basins). These lush rain-forest regions, whose immense vegetation growth is attributed to monsoon rains, contain some of the most prolific and widely speciated regions on earth for a wide variety of flora and fauna. Toward the northern and southern limits are low-latitude savannasavanna
, tropical or subtropical grassland lying on the margin of the trade wind belts. The climate of a savanna is characterized by a rainy period during the summer when the area is covered by grasses, and by a dry winter when the grasses wither.
..... Click the link for more information. , steppesteppe
, temperate grassland of Eurasia, consisting of level, generally treeless plains. It extends over the lower regions of the Danube and in a broad belt over S and SE European and Central Asian Russia, stretching E to the Altai and S to the Transbaykal and Manchurian plains.
..... Click the link for more information. , and desertdesert,
arid region, usually partly covered by sand, having scanty vegetation or sometimes almost none, and capable of supporting only a limited and specially adapted animal population.
..... Click the link for more information. climates (with decreasing seasonal rainfall). Tropical highland climates, which have the characteristics of temperate climates, also occur where high mountain ranges lie in the zone. High temperatures and rainfall make rubber, tea, coffee, cocoa, spices, bananas, pineapples, oils and nuts, and lumber the leading agricultural exports of the countries in the tropical zone. Progress in tropical medicine, advancing technology, and the pressure of increasing populations have led in recent years to the cultivation and settlement of some rain-forest areas. Such population growth has led to deforestation of the tropical forest, which is believed to contribute to the greenhouse effect and global warmingglobal warming,
the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. Global warming and its effects, such as more intense summer and winter storms, are also referred to as climate
..... Click the link for more information. , and to the elimination of numerous unique species.
See P. Gourou, The Tropical World (4th ed. 1966); B. W. Hodder, Economic Development in the Tropics (1968); P. W. Richards, The Life of the Jungle (1970); F. Bourliere, Tropical Savannas (1983).
Any portion of the earth characterized by a tropical climate.