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The trade winds are the prevailing pattern of easterly surface winds found in the tropics, within the lower portion of the Earth's atmosphere, in the lower section of the troposphere near the Earth's equator. The trade winds blow predominantly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere, strengthening during the winter and when the Arctic oscillation is in its warm phase. Historically, the trade winds have been used by captains of sailing ships to cross the world's oceans for centuries, and enabled European empire expansion into the Americas and trade routes to become established across the Atlantic and Pacific oceans. In meteorology, the trade winds act as the steering flow for tropical storms that form over the Atlantic, Pacific, and southern Indian Oceans and make landfall in North America, Southeast Asia, and Madagascar and eastern Africa, respectively. Trade winds also transport African dust westward across the Atlantic Ocean into the Caribbean Sea, as well as portions of southeastern North America. Shallow cumulus clouds are seen within trade wind regimes, and are capped from becoming taller by a trade wind inversion, which is caused by descending air aloft from within the subtropical ridge. The weaker the trade winds become, the more rainfall can be expected in the neighboring landmasses. == History == The term ''trade winds'' originally derives from the early fourteenth century late Middle English word 'trade,' meaning "path" or "track." The Portuguese recognized the importance of the trade winds in navigation in both the north and south Atlantic ocean as early as the 15th century. They learned that to reach South Africa, they needed to go far out in the ocean, head for Brazil and around 30°S, and then go east again. Following the African coast southbound means upwind in the Southern hemisphere. In the Pacific ocean, the full wind circulation, which included both the trade wind easterlies and higher-latitude Westerlies, was unknown to Europeans until Andres de Urdaneta's voyage in 1565. The captain of a sailing ship seeks a course along which the winds can be expected to blow in the direction of travel. During the Age of Sail, the pattern of prevailing winds made various points of the globe easy or difficult to access, and therefore had a direct impact on European empire-building and thus on modern political geography. For example, Manila galleons could not sail into the wind at all.〔 By the 18th century the importance of the trade winds to England's merchant fleet for crossing the Atlantic Ocean had led both the general public and etymologists to identify the name with a later meaning of 'trade', "(foreign) commerce". Between 1847 and 1849, Matthew Fontaine Maury collected enough information to create wind and current charts for the world's oceans. The French word, also a women's name, Alizé or Alizée ((:a.li.ze), means trade winds. Examples are: Alizée and Alizé Cornet. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Trade winds」の詳細全文を読む スポンサード リンク
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