Prevailing winds

Prevailing winds

The prevailing winds are the trends in speed and direction of wind over a particular point on the earth's surface. A region's prevailing winds often showglobal patterns of movement in the earth's atmosphere. Prevailing winds are the causes of waves as they push the ocean.

Geostrophic winds

The prevailing surface winds are calm at the equator (the doldrums). From the equator, they blow from the northeast immediately north of the equator and from the southeast immediately south of the equator. These are called the trade winds, a name which derives from the Middle English meaning of "trade" meaning "track" or "path." Around 25 degrees north and south, near the tropics, the winds calm again in the horse latitudes.

Most of this activity is due to air pressure. At the equator, the heat causes air to rise, creating a belt of low pressure in the doldrums. After the air rises, it flows north and south high in the atmosphere until it cools enough to subside, creating belts of high pressure in the horse latitudes. All of the extra air has to go somewhere, so it blows towards the equator as the trade winds, and towards the middle latitudes as the prevailing westerlies.

Meanwhile, at the poles, the cold causes air to subside, increasing the air pressure to cause the polar highs. As with the horse latitudes, the extra air has to flow somewhere, so it flows back in the direction of the equator as the polar easterlies, creating the far northern and southern climates of the world.

References

* [http://www.ace.mmu.ac.uk/eae/Climate/Older/Prevailing_Winds.html Prevailing winds] at Manchester Metropolitan University
* [http://www.infoplease.com/ce6/weather/A0861968.html Prevailing winds and general circulation patterns] at InfoPlease encyclopedia


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • prevailing winds — The winds produced by the global patterns of barometric pressure, both at the surface and aloft. The prevailing winds are influenced by the earth’s rotation (Coriolis effect). The prevailing winds are the polar high, polar easterlies, subpolar… …   Aviation dictionary

  • prevailing — prevailing, prevalent, rife, current are comparable when they mean general (as in circulation, acceptance, or use) especially in a given place or at a given time. Prevailing applies especially to something which is predominant or which generally… …   New Dictionary of Synonyms

  • Prevailing — is synonymous with dominant: *Prevailing winds *Prevailing visibility *Prevailing wage …   Wikipedia

  • prevailing wind — UK / US noun [countable] Word forms prevailing wind : singular prevailing wind plural prevailing winds a wind that blows in a particular area at a particular time of year …   English dictionary

  • prevailing — prevailingly, adv. prevailingness, n. /pri vay ling/, adj. 1. predominant: prevailing winds. 2. generally current: the prevailing opinion. 3. having superior power or influence. 4. effectual. [1580 90; PREVAIL + ING2] Syn. 1 …   Universalium

  • prevailing — [[t]prɪve͟ɪlɪŋ[/t]] ADJ: ADJ n The prevailing wind in an area is the type of wind that blows over that area most of the time. The direction of the prevailing winds should be taken into account …   English dictionary

  • prevailing — pre•vail•ing [[t]prɪˈveɪ lɪŋ[/t]] adj. 1) most frequent; predominant: prevailing winds[/ex] 2) generally current: the prevailing opinion[/ex] 3) having superior power or influence • Etymology: 1580–90 pre•vail′ing•ly, adv …   From formal English to slang

  • prevailing — adjective most frequent or common prevailing winds • Syn: ↑prevalent, ↑predominant, ↑dominant, ↑rife • Similar to: ↑frequent • Derivationally related forms: ↑ …   Useful english dictionary

  • prevailing westerlies — noun plural : the average or normal westerly winds of the middle latitudes * * * prevailing westerlies, the usual westerly winds that blow between 30 degrees and 60 degrees latitude, both north and south of the equator …   Useful english dictionary

  • prevailing westerly — noun the winds from the west that occur in the temperate zones of the Earth • Syn: ↑westerly • Derivationally related forms: ↑westerly (for: ↑westerly) • Hypernyms: ↑west wind, ↑ …   Useful english dictionary

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”