A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by names such as hurricane (<span>/<span>ˈhʌrᵻkən</span>/</span> or <span>/<span>ˈhʌrᵻkeɪn</span>/</span>[1][2][3]), typhoon <span>/<span>taɪˈfuːn</span>/</span>, tropical storm, cyclonic storm, tropical depression, and simply cyclone.[4] A hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean.[4]
Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface, which ultimately recondenses into clouds and rain when moist air rises and cools to saturation. This energy source differs from that of mid-latitude cyclonic storms, such as nor'easters and European windstorms, which are fueled primarily by horizontal temperature contrasts. The strong rotating winds of a tropical cyclone are a result of the conservation of angular momentum imparted by the Earth's rotation as air flows inwards toward the axis of rotation. As a result, they rarely form within 5° of the equator.[5] Tropical cyclones are typically between 100 and 2,000 km (62 and 1,243 mi) in diameter.
Tropical refers to the geographical origin of these systems, which form almost exclusively over tropical seas. Cyclone refers to their cyclonic nature, with wind blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. The opposite direction of circulation is due to the Coriolis effect.
In addition to strong winds and rain, tropical cyclones are capable of generating high waves, damaging storm surge, and tornadoes. They typically weaken rapidly over land where they are cut off from their primary energy source. For this reason, coastal regions are particularly vulnerable to damage from a tropical cyclone as compared to inland regions. Heavy rains, however, can cause significant flooding inland, and storm surges can produce extensive coastal flooding up to 40 kilometres (25 mi) from the coastline. Though their effects on human populations are often devastating, tropical cyclones can relieve drought conditions. They also carry heat energy away from the tropics and transport it toward temperate latitudes, which may play an important role in modulating regional and global climate.
<span>Part of a series onTropical cyclonesFormation and naming[show]Effects[show]Climatology and tracking[show]Tropical cyclone naming[show]<span>Outline of tropical cyclonesTropical cyclones portal</span><span>vte</span></span>Contents <span> [hide] </span><span><span><span>1Physical structure</span><span><span>1.1Wind field</span><span>1.2Eye and center</span><span>1.3Size</span></span></span><span><span>2Physics and energetics</span><span><span>2.1Secondary circulation: a Carnot heat engine</span><span>2.2Primary circulation: rotating winds</span><span><span>2.3Maximum potential intensity</span><span><span>2.3.1Derivation</span><span>2.3.2Characteristic values and variability on Earth</span></span></span><span>2.4Interaction with the upper ocean</span></span></span><span>3Major basins and related warning centers</span><span><span>4Formation</span><span><span>4.1Times</span><span>4.2Factors</span><span>4.3Locations</span></span></span><span><span>5Movement</span><span><span>5.1Environmental steering</span><span>5.2Beta drift</span><span>5.3Multiple storm interaction</span><span>5.4Interaction with the mid-latitude westerlies</span><span>5.5Landfall</span></span></span><span><span>6Dissipation</span><span><span>6.1Factors</span><span>6.2Artificial dissipation</span></span></span><span>7Effects</span><span><span>8Observation and forecasting</span><span><span>8.1Observation</span><span>8.2Forecasting</span></span></span><span><span>9Classifications, terminology, and naming</span><span><span><span>9.1Intensity classifications</span><span><span>9.1.1Tropical depression</span><span>9.1.2Tropical storm</span><span>9.1.3Hurricane or typhoon</span></span></span><span>9.2Origin of storm terms</span><span>9.3Naming</span></span></span><span>10Notable tropical cyclones</span><span>11Changes caused by El Niño-Southern Oscillation</span><span>12Long-term activity trends</span><span>13Global warming</span><span>14Related cyclone types</span><span>15In popular culture</span><span>16See also</span><span>17References</span><span>18<span>External links
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