Kathryn Posted March 2, 2007 Report Share Posted March 2, 2007 The following was summarized from information on the Wikipedia web site. The tropics are the geographic region centered on the equator and limited in latitude by the Tropic of Cancer at approximately 23°30' N latitude and the Tropic of Capricorn at 23°30' S latitude. The word "tropics" comes from Greek tropos meaning "turn", because the apparent position of the Sun oscillates between the two tropics with a period that defines the average length of a year. In the Tropics, the sun is directly overhead at least once during the year - at the edges of the tropics this occurs at the summer solstice and over the equator at the equinoxes. This is the hottest part of the earth, and there are two annual seasons: a dry and a wet. This zone includes most of Africa, southern India, southern Asia, Indonesia, New Guinea, northern Australia, Central America and northern South America. Tropical plants and animals are those species native to the tropics. Tropical is also sometimes used in a general sense for a tropical climate, a climate that is warm to hot and moist year-round, often with the sense of lush vegetation. However, there are places in the tropics that are anything but "tropical" in this sense, with even alpine tundra and snow-capped peaks, including Mauna Kea, Mt. Kilimanjaro, and the Andes as far south as the northernmost parts of Chile and Argentina. Places in the tropics which are drier with low humidity but extreme heat are such as the Sahara Desert and Central Africa and Northern Australian Outback. The subtropics refers to the zones immediately north and south of the tropic zone. The term can be used loosely to mean a range of latitudes between 23.5 and approximately 40 degrees. These areas typically have hot summers-- even hotter than tropical climates. A subtropical climate implies that the air temperature usually does not go below freezing (0°C or 32°F). This is a threshold temperature for a gamut of plants, and applies to coastal California, Florida, northern India, most of eastern Australia, Texas, and coastal South Africa, for example. The poleward limit of such climates is higher on the west coasts of the northern continents and lower on the east coasts, because occasional Winter cold snaps reach farther south in the east. Some subtropical cities include New Delhi, Hong Kong, Athens, Curitiba, Cairo, Mexico City, Miami, Los Angeles, Houston, New Orleans, Brunswick, Georgia, Orlando, Tampa and Brisbane. Cities such as Darwin, Townsville and Cairns are not subtropical, and have truly tropical climates. In certain areas of the world the subtropics are plagued by hurricanes, typhoons or tropical cyclones that originate in the tropics in the summer and fall. Subtropical locations don't usually have distinctly wet or dry seasons, and have a fairly even distribution of rain throughout the year. At latitudes closer to the poles, the subtropical climate gives way to a "temperate" climate, characterized by annual mean temperatures of less than 20°C or 68°F and warmest month average temperatures of over 10°C or 50°F. In the two Temperate Zones, the sun is never directly overhead, and the climate is mild, generally ranging from warm to cool. The changes in these regions between summer and winter are generally subtle, warm or cool, rather than extreme, burning hot or freezing cold. However, a temperate climate can have very unpredictable weather. One day it may be sunny, the next it may be raining, and after that it may be cloudy. These erratic weather patterns occur in summer as well as winter. The north temperate zone extends from the Tropic of Cancer at about 23.5 degrees north latitude to the Arctic Circle at about 66.5 degrees north latitude and includes Great Britain, Europe, northern Asia and North America. The south temperate zone extends from the Tropic of Capricorn at about 23.5 degrees south latitude to the Antarctic Circle at about 66.5 degrees south latitude and includes southern Australia, New Zealand and southern South America. Within these borders there are many individual climate types, which are generally grouped into two categories: continental and maritime. The maritime climate is clearly affected by the oceans, which help to sustain somewhat stable temperatures throughout the year. In the temperate zones, the prevailing winds are from the west, the western edge of temperate continents most commonly experience this maritime climate. Such regions include Western Europe, especially the UK, and western North America at latitudes between 40° and 60° north (65°N in Europe). The continental climate is usually situated inland, with warmer summers and colder winters. The large land mass increases its effects on heat reception and loss. In North America, the Rocky Mountains act as a climate barrier to the maritime air blowing from the west, creating a continental climate to the east. In Europe, the maritime climate is able to stabilize temperatures further inland, because the major mountain range - the Alps - is oriented east-west. The two Frigid Zones, or polar regions, experience the midnight sun and the polar night for part of the year - the edge of the zone experiences one day at the solstice when the sun doesn't rise or set for 24 hours, while in the centre of the zone (the pole), this occurs all year round. The Frigid Zones are the coldest parts of the earth, and are covered with ice and snow. The North Frigid Zone (the Arctic) includes Greenland, northern Scandinavia, northern Russia, and the Arctic ice. The South Frigid Zone (The Antarctic) is filled by the continent of Antarctica; the next closest mainland is the southern tip of Chile and Argentina. Click Here to Join the IPS Today! Click Here to Renew Your IPS Membership! Link to comment Share on other sites More sharing options...
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