| definition |
- (Also called hot wave, warm wave.) A period of abnormally and uncomfortably hot and usually humid weather. To be a heat wave such a period should last at least one day, but conventionally it lasts from several days to several weeks. In 1900, A. T. Burrows more rigidly defined a "hot wave" as a spell of three or more days on each of which the maximum shade temperature reaches or exceeds 90°F. More realistically, the comfort criteria for any one region are dependent upon the normal conditions of that region. In the eastern United States, heat waves generally build up with southerly winds on the western flank of an anticyclone centered over the southeastern states, the air being warmed by passage over a land surface heated by the sun.
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| Abstract from DBPedia | A heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual climate in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area. The term is applied both to hot weather variations and to extraordinary spells of hot weather which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, increased risk of wildfires in areas with drought, and widespread power outages due to increased use of air conditioning. A heat wave is considered extreme weather, and poses danger to human health because heat and sunlight overwhelm the human body's cooling system. Heat waves can usually be detected using forecasting instruments so that a warning can be issued. According to the IPCC, heatwaves have become more frequent, and over land more intense, almost everywhere since the 1950s, due to climate change. Heatwaves often have complex effects on human economies, due to less productivity of workers, disruption of agricultural and industrial processes and damage to infrastructure not adapted for extreme heat. Recent projections suggest heatwaves alone will cause ~1% decrease of GDP to economies by mid 21st century.熱波（ねっぱ、英: heat wave）は、その地域の平均的な気温に比べて著しく高温な気塊が波のように連続して押し寄せてくる現象のことである。 世界気象機関（WMO）の定義では、日中の最高気温が平均最高気温を5°C以上上回る日が5日間以上連続した場合をいう。熱波の定義は地域によって異なる。 (Source: http://dbpedia.org/resource/Heat_wave) |
