FACTOID # 26: Delaware is the latchkey kid capital of America, with 71.8% of households having both parents in the labor force.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Anticyclone" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Anticyclone

In meteorology, an anticyclone (that is, opposite to a cyclone) is a weather phenomenon in which there is a descending movement of the air and a high pressure area over the part of the planet's surface affected by it. Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ... Radar image of a tropical cyclone in the northern hemisphere. ... Weather is a term that encompasses phenomena in the atmosphere of a planet. ... A meteorological phenomenon is one of several commonplace or unusual weather events which illuminate and are explained by the principles of meteorology. ... A high, high-pressure cell, or high pressure area is a region where the atmospheric pressure is greater than the surrounding area. ... The eight planets and three dwarf planets of the Solar System. ...

Contents

Terminology

Confusion may be created by the fact that the term subtropical anticyclone is used by meteorologists in Australia in place of extratropical anticyclone, which is the term used in the United States. Except for the wordage, there is no difference; there are no separate or different types of warm dry air anticyclones being generated by the ITCZ. Both extratropical cyclones and subtropical anticyclones are seen in the Northern Hemisphere, year-round. For an example of the Australian term, see: Equatorial trough A fictitious synoptic chart of an extratropical cyclone affecting the UK & Ireland. ...


Origin

The notable scientist Sir Francis Galton proposed the existence of the anticyclone a part of his work in weather and writing Meteorographica, or Methods of Mapping the Weather (1863). Galton's anticyclone hypothesis was eventually confirmed with the discovery of the anticyclone which enabled meteorologists to draw the modern weather map.[citation needed]Early versions of surface weather analysis charts produced prior to 1863 depicted cyclones, but not anticyclones. Sir Francis Galton F.R.S. (February 16, 1822 – January 17, 1911), half-cousin of Charles Darwin, was an English Victorian polymath, anthropologist, eugenicist, tropical explorer, geographer, inventor, meteorologist, proto-geneticist, psychometrician, and statistician. ... Weather is a term that encompasses phenomena in the atmosphere of a planet. ... A surface weather analysis for the United States on October 21, 2006. ... Radar image of a tropical cyclone in the northern hemisphere. ...


Formation

All anticyclones are produced by dry air that settles to the surface of the earth and accumulates, forming air masses. The absence of aqueous vapor (water vapor) increases the density of air which means that each volumetric unit of dry air weighs more than the same volumetric unit of humid air at the same temperature and pressure. The two most common parts of the air are nitrogen (roughly 78% of the total) and oxygen (roughly 21% of the total). Together, the two components weigh more than 99% of the total weight of the atmosphere. When air takes on aqueous vapor (water vapor), vapor pressure displaces some of the heavier nitrogen and oxygen, thus, a mixture that is lighter in weight overall is created. Displacement by vapor pressure produces intense tropical storms called hurricanes or typhoons. Air mass - Wikipedia /**/ @import /skins-1. ... It has been suggested that multiple sections of steam be merged into this article or section. ... The density of air, ρ (Greek: rho) (air density), is the mass per unit volume of Earths atmosphere, and is a useful value in aeronautics. ... Fig. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... In chemistry and physics, Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... In chemistry and physics, Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... This article is about weather phenomena. ... This article is about weather phenomena. ...


Anticyclogenesis

Main article; Anticyclogenesis

Anticyclogenesis is the development or strengthening of anticyclonic circulation in the atmosphere. ...

Cool or cold dry air type

Cool or cold dry air settles onto land and forms shallow anticyclones or high-pressure cells which often move across the terrain and create fair weather with little cloudiness or precipitation, then dissipate and vanish after reaching the open sea. The types of anticyclones display different patterns of movement. High pressure area - Wikipedia /**/ @import /skins-1. ...


High-latitudes maritime type

In the months of winter, many strong cyclones appear at high latitudes. Rising air in them eventually descends to form anticyclones. Tall anticyclones appear at some places each year during the coldest months. They may exceed 35,000 feet or 10,200 meters in height. The position of each anticyclone is at about the same place on the surface as it is the air far above the surface. The sea-level pressure may exceed 1040 millibars (hectopascals) (hPa) (SI). They tend to linger close to the place at which they had appeared. Radar image of a tropical cyclone in the northern hemisphere. ... Sea-level pressure or mean sea-level pressure (MSL or MSLP) is the standard that different weather stations employ to compare barometric pressure readings, which are made in inches of mercury. ... A millibar (mbar, also mb) is 1/1000th of a bar, a unit for measurement of pressure. ... The pascal (symbol Pa) is the SI unit of pressure. ... Look up si, Si, SI in Wiktionary, the free dictionary. ...


The Denmark Strait along the east coast of Greenland is a place where they often appear, particularly during the winter. They form part of the North Atlantic Oscillation that significantly influences the weather in that region of the Northern Hemisphere. The Beaufort Sea is an arm of the Arctic Ocean that exists north of northwestern Canada. An anticyclone called the Arctic High or the Beaufort High forms there. NSIDC The Denmark Strait is a strait between Greenland and Iceland. ... The North Atlantic oscillation (NAO) is a complex climatic phenomenon in the North Atlantic Ocean (especially associated with fluctuations of climate between Iceland and the Azores). ... Approximate area of the Beaufort Sea, and the disputed waters The Beaufort Sea is a large body of water north of The Northwest Territories, the Yukon, and Alaska and west of Canadas arctic islands that is a part of the Arctic Ocean. ...


Warm, dry air type

An anticyclone composed of warm dry air may be situated over much of the North Atlantic ocean during most of the year. The warm dry air type of anticyclone is tall and may be observed on weather charts above three miles (5km) in height. The warm dry air type of anticyclone is usually described as being semipermanent. Frontal activity is not associated with it. Transoceanic in extent, in Europe it is called the Azores High, and in the United States it is known by the name Bermuda High. The Atlantic Ocean is Earths second-largest ocean, covering approximately one_fifth of its surface. ... World map showing the location of Europe. ... Motto Antes morrer livres que em paz sujeitos Rather die free than in peace subjugated Anthem A Portuguesa (national) Hino dos Açores (local) Capital Ponta Delgada1 Angra do Heroísmo2 Horta3 Largest city Ponta Delgada Official languages Portuguese Government Autonomous region  -  President Carlos César Establishment  -  Settled 1439   -  Autonomy...


Since it has a tropical origin, its most proper name is extratropical anticyclone (but see "Terminology," above). It has a characteristic "vertical displacement" that shifts its center away from its surface position towards the equator and westwards, too. Far above the surface of the North Atlantic ocean at a height of 3-4 miles (5-7km), the center of the high-pressure cell may be seen about 3,000 miles (5,000 km) southwestwards of its surface position (which is in the general vicinity of the Azores Islands). The Atlantic Ocean is Earths second-largest ocean, covering approximately one_fifth of its surface. ... High pressure area - Wikipedia /**/ @import /skins-1. ... Motto Antes morrer livres que em paz sujeitos Rather die free than in peace subjugated Anthem A Portuguesa (national) Hino dos Açores (local) Capital Ponta Delgada1 Angra do Heroísmo2 Horta3 Largest city Ponta Delgada Official languages Portuguese Government Autonomous region  -  President Carlos César Establishment  -  Settled 1439   -  Autonomy...


The maximum sea-level pressure in this type of anticyclone is not very high. It may reach, perhaps, 1025 millibars (hectopascals) or thereabouts during the summertime, which is a mere twelve millibars above the average sea-level pressure of 1013 millibars. Sea-level pressure or mean sea-level pressure (MSL or MSLP) is the standard that different weather stations employ to compare barometric pressure readings, which are made in inches of mercury. ... A millibar (mb) is 1/1000th of a bar, a unit for measurement of pressure. ... The pascal (symbol Pa) is the SI unit of pressure. ...


Similar anticyclones that are built of warm dry air exist over other oceanic areas of the world, such as the South Atlantic ocean. The anticyclone that is located there is practically a mirror-image of the anticyclone that is located over the North Atlantic ocean. Its "vertical displacement" is also towards the equator and westwards, too. The warm dry air is continually being produced in the Intertropical convergence zone (ITCZ) by thunderstorms. The Atlantic Ocean is Earths second-largest ocean, covering approximately one_fifth of its surface. ... The Atlantic Ocean is Earths second-largest ocean, covering approximately one_fifth of its surface. ... The thunderstorms of the Intertropical Convergence Zone form a line across the eastern Pacific Ocean. ...


Structure

At the surface the air tends to flow outwards in all directions from the central area of high pressure, and is deflected on account of the earth's rotation (see Coriolis effect) so as to give a spiral movement. In the northern hemisphere an anticyclone rotates in the clockwise direction, while it rotates counterclockwise in the southern hemisphere. The rotation is caused by the movement of colder higher pressure air that is moving away from the poles towards the equator being affected by the rotation of the earth. Since the air in an anticyclone is descending, it becomes warmed and dried, and therefore transmits radiation freely whether from the sun to the earth or from the earth into space. In the inertial frame of reference (upper part of the picture), the black object moves in a straight line. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ...


Anticyclones generally bring fair weather and clear skies as the dynamics of an anticyclone lead to downward vertical movement which suppresses convective activity and generally lowers the mean relative humidity, in contrast to the upward vertical movement in a cyclone. However as the anticyclone moves over the earth surface it may heat up locally, acquire water from the land or oceans or encounter warmer wet air.

Image File history File links Wiki_letter_w. ...

Evolution

Image File history File links Wiki_letter_w. ...

Motion

Image File history File links Wiki_letter_w. ...

Effects

In winter the anticyclonic weather is characterized by clear air with periods of frost, causing fogs in towns and low-lying damp areas, and in summer by still cloudless days with gentle variable airs and fine weather. The low, sharp inversion can lead to areas of persistent stratocumulus or stratus cloud, colloquially known as Anticyclonic gloom. The type of weather brought about by an anticyclone depends on its origin. For example, extensions of the Azores high pressure may bring about anticyclonic gloom during the winter, as they are warmed at the base and will trap moisture as they move over the warmer oceans. High pressures that build to the north and extend southwards will often bring clear weather. This is due to being cooled at the base (as opposed to warmed) which helps prevent clouds from forming. This article or section does not cite its references or sources. ... A stratocumulus cloud is a cloud belonging to a class characterized by large dark, rounded masses, usually in groups, lines, or waves, the individual elements being larger than those in altocumulus and the whole being at a lower altitude, usually below 2400 m (8000 ft). ... A Stratus cloud is a cloud belonging to a class characterized by horizontal layering with a uniform base, as opposed to convective clouds that are as tall or taller than wide (these are termed Cumulus clouds). ...


Local geography may cause a range of localised weather phenomena specific to anticyclones, while the interaction of the different air masses, which occurs at weather fronts, may cause a range of weather events. In meteorology, an air mass is a large volume of air having fairly uniform characteristics of temperature, atmospheric pressure, and water vapor content. ... A guide to the symbols for weather fronts that may be found on a weather map. ...

Image File history File links Wiki_letter_w. ...

Anticyclonic storms

The Great Red Spot on Jupiter is an example of an Anticyclonic storm The Great Red Spot is a persistent anticyclonic storm on the planet Jupiter, 22° south of the equator, which has lasted at least 340 years. ...

Image File history File links Wiki_letter_w. ...

References

    • This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.

    Encyclopædia Britannica, the 11th edition The Encyclopædia Britannica Eleventh Edition (1910–1911) is perhaps the most famous edition of the Encyclopædia Britannica. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...

    See also

    Cyclones and Anticyclones of the world
    v  d  e
    Extratropical - Meso-scale - Polar - Polar low - Subtropical - Tropical
    Tropical cyclones Portal

    Radar image of a tropical cyclone in the northern hemisphere. ... A fictitious synoptic chart of an extratropical cyclone affecting the UK & Ireland. ... It has been suggested that this article or section be merged into Supercell. ... Polar cyclones (also known as Arctic Cyclones) are vast areas of low pressure. ... Polar low over the Barents Sea on February 27, 1987 A polar low is a small-scale, short-lived atmospheric low pressure system (depression) that is found over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. ... A subtropical cyclone is a weather system that has some characteristics of a tropical cyclone and some characteristics of an extratropical cyclone. ... Cyclone Catarina, a rare South Atlantic tropical cyclone viewed from the International Space Station on March 26, 2004 Hurricane and Typhoon redirect here. ... Image File history File links Download high resolution version (1000x662, 320 KB) http://eol. ... Atmospheric circulation is the large-scale movement of air, and the means (together with the ocean circulation, which is smaller [1]) by which heat is distributed on the surface of the Earth. ... Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ... Blocks in meteorology are large scale patterns in the atmospheric pressure field that are nearly stationary, effectively blocking or redirecting migratory cyclones. ... In physics, the Coriolis effect is an inertial force first described by Gaspard-Gustave Coriolis, a French scientist, in 1835. ... Radar image of a tropical cyclone in the northern hemisphere. ... Layers of Atmosphere - not to scale (NOAA)[2] Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ... A high, high-pressure cell, or high pressure area is a region where the atmospheric pressure is greater than the surrounding area. ... North American High - Wikipedia /**/ @import /skins-1. ... A pressure system is a region of the Earths atmosphere where air pressure is unusually high or low. ... The Siberian High is a massive collection of cold or very cold dry air that accumulates on the Eurasian terrain for much of the year. ... An anticyclonic tornado is a tornado which rotates in a clockwise direction in the Northern Hemisphere and a counterclockwise direction in the Southern Hemisphere. ... The Great Red Spot is a persistent anticyclonic storm on the planet Jupiter, 22° south of the equator, which has lasted at least 340 years. ...

    External links


      Results from FactBites:
     
    Reference.com/Encyclopedia/Anticyclone (1116 words)
    All anticyclones are produced by dry air that settles to the surface of the earth and accumulates, forming air masses.
    Anticyclones generally bring fair weather and clear skies as the dynamics of an anticyclone lead to downward vertical movement which suppresses convective activity and generally lowers the mean relative humidity, in contrast to the upward vertical movement in a cyclone.
    In winter anticyclonic weather is characterized by clear air with periods of frost, causing fogs in towns and low-lying damp areas, and in summer by still cloudless days with gentle variable airs and fine weather.
    anticyclone - HighBeam Encyclopedia (364 words)
    anticyclone region of high atmospheric pressure; anticyclones are commonly referred to as "highs." The pressure gradient, or change between the core of the anticyclone and its surroundings, combined with the Coriolis effect, causes air to circulate about the core in a clockwise direction in the Northern Hemisphere and a counterclockwise direction in the Southern Hemisphere.
    Many low-level anticyclones are swept generally eastward by the prevailing west-to-east flow of the upper atmosphere, usually traversing some 500 to 1,000 mi (800-1,600 km) per day.
    The term anticyclone is derived from the fact that the associated rotational direction and general weather characteristics of an anticylone are opposite to those of a cyclone.
      More results at FactBites »

     
     

    COMMENTARY     


    Share your thoughts, questions and commentary here
    Your name
    Your comments

    Want to know more?
    Search encyclopedia, statistics and forums:

     


    Press Releases |  Feeds | Contact
    The Wikipedia article included on this page is licensed under the GFDL.
    Images may be subject to relevant owners' copyright.
    All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
    Usage implies agreement with terms, 1022, m