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Polar vortex
 
 
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The polar vortex is a persistent, large-scale cyclone
Cyclone

In meteorology, a cyclone refers to an area of closed, circular fluid motion rotating in the same direction as the Earth's rotation. This is usually characterized by inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth....
 located near the Earth's poles
Poles

The Polish people, or Poles , are a West Slavs ethnic group of Central Europe, living predominantly in Poland. Poles are sometimes defined as people who share a common Polish culture and are of Polish descent....
, in the middle and upper troposphere
Troposphere

The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and particulate....
 and the stratosphere
Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down....
. It surrounds the polar high
Polar high

The polar highs are areas of high atmospheric pressure around the north pole and south poles, south polar high being the stronger one because land gains and losses heat more effectively than sea....
s and is part of the polar front
Polar front

In meteorology, the polar front is the boundary between the polar cell and the Ferrel cell in each hemisphere. At this boundary a sharp gradient in temperature occurs between these two air masses, each at very different temperatures....
.
vortex
Vortex

A vortex is a Rotation, often Turbulence,flow of fluid. Any spiral motion with closed Streamlines, streaklines and pathlines is vortex flow....
 is most powerful in the hemisphere
Sphere

A sphere is a symmetrical geometrical object. In non-mathematical usage, the term is used to refer either to a round ball or to its two-dimensional surface....
's winter, when the temperature gradient
Temperature gradient

A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location....
 is steepest, and diminishes or can disappear in the summer. The Antarctic polar vortex is more pronounced and persistent than the Arctic
Arctic

The Arctic is the region around the Earth's North Pole, opposite the Antarctica region around the South Pole. The Arctic includes the Arctic Ocean and parts of Canada, Greenland , Russia, the United States , Iceland, Norway, Sweden and Finland....
 one; this is because the distribution of land masses at high latitudes in the northern hemisphere gives rise to Rossby wave
Rossby wave

Rossby waves are giant meanders in high-altitude winds that are a major influence on weather. Their emergence is due to shear in rotating fluids, so that the Coriolis force changes along the sheared coordinate....
s which contribute to the breakdown of the vortex, whereas in the southern hemisphere the vortex remains less disturbed.






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Encyclopedia


The polar vortex is a persistent, large-scale cyclone
Cyclone

In meteorology, a cyclone refers to an area of closed, circular fluid motion rotating in the same direction as the Earth's rotation. This is usually characterized by inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth....
 located near the Earth's poles
Poles

The Polish people, or Poles , are a West Slavs ethnic group of Central Europe, living predominantly in Poland. Poles are sometimes defined as people who share a common Polish culture and are of Polish descent....
, in the middle and upper troposphere
Troposphere

The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and particulate....
 and the stratosphere
Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down....
. It surrounds the polar high
Polar high

The polar highs are areas of high atmospheric pressure around the north pole and south poles, south polar high being the stronger one because land gains and losses heat more effectively than sea....
s and is part of the polar front
Polar front

In meteorology, the polar front is the boundary between the polar cell and the Ferrel cell in each hemisphere. At this boundary a sharp gradient in temperature occurs between these two air masses, each at very different temperatures....
.

Arctic and Antarctic variation

The vortex
Vortex

A vortex is a Rotation, often Turbulence,flow of fluid. Any spiral motion with closed Streamlines, streaklines and pathlines is vortex flow....
 is most powerful in the hemisphere
Sphere

A sphere is a symmetrical geometrical object. In non-mathematical usage, the term is used to refer either to a round ball or to its two-dimensional surface....
's winter, when the temperature gradient
Temperature gradient

A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location....
 is steepest, and diminishes or can disappear in the summer. The Antarctic polar vortex is more pronounced and persistent than the Arctic
Arctic

The Arctic is the region around the Earth's North Pole, opposite the Antarctica region around the South Pole. The Arctic includes the Arctic Ocean and parts of Canada, Greenland , Russia, the United States , Iceland, Norway, Sweden and Finland....
 one; this is because the distribution of land masses at high latitudes in the northern hemisphere gives rise to Rossby wave
Rossby wave

Rossby waves are giant meanders in high-altitude winds that are a major influence on weather. Their emergence is due to shear in rotating fluids, so that the Coriolis force changes along the sheared coordinate....
s which contribute to the breakdown of the vortex, whereas in the southern hemisphere the vortex remains less disturbed. The breakdown of the polar vortex is an extreme event known as a Sudden Stratospheric Warming
Sudden stratospheric warming

A sudden stratospheric warming is an event where the polar vortex of westerly winds in the Northern winter hemisphere abruptly slows down or even reverses direction, accompanied by a rise of stratospheric temperature by several tens of kelvins....
, here the vortex completely breaks down and an associated warming of 30-50 degrees over a few days can occur. The Arctic vortex is elongated in shape, with two centres, one roughly over Baffin Island
Baffin Island

Baffin Island in the territory of Nunavut is the largest member of the Canadian Arctic Archipelago. It is the List of Canadian islands by area and the List of islands by area, with an area of and has a population of 11,000 ....
 in Canada
Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
 and the other over northeast Siberia
Siberian High

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. It reaches its greatest size and strength in the winter, when the air temperature near the center of the high-pressure cell or anticyclone is often lower than -40 ?C ....
.

Ozone depletion

The chemistry of the Antarctic polar vortex has created severe ozone depletion
Ozone depletion

Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total volume of ozone in Earth stratosphere since the late 1970s, and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period....
. The nitric acid in polar stratospheric cloud
Polar stratospheric cloud

Polar stratospheric clouds , also known as nacreous clouds, are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 metres ....
s reacts with CFCs to form chlorine
Chlorine

Chlorine...
, which catalyzes
Catalysis

Catalysis is the process in which the reaction rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst....
 the photochemical destruction of ozone
Ozone

Ozone or trioxygen is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic O2....
. Chlorine concentrations build up during the winter polar night, and the consequent ozone destruction is greatest when the sunlight returns in spring (September/October). These clouds can only form at temperatures below about -80°C
Celsius

Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death....
. Since these temperatures are rarely reached in the Arctic, ozone depletion at the north pole is much less severe than at the south. Accordingly, the seasonal reduction of ozone levels over the Arctic is characterized as an "ozone dent," whereas the more severe ozone depletion over the Antarctic is considered an "ozone hole."

Duration

The Antarctic Polar Vortex forms during the polar winter. The ozone hole lasts from August to November.

Outside earth

Other astronomical bodies are also known to have polar vortices, including Venus
Venus

Venus is the second-closest planet to the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus , the Roman mythology goddess of love....
 (double vortex - that is, two polar vortices at a pole ), Mars
MARS

In cryptography, MARS is a block cipher that was IBM's submission to the Advanced Encryption Standard process. MARS was selected as an AES finalist in August 1999, after the AES2 conference in March 1999, where it was voted as the fifth and last finalist algorithm....
, Jupiter
Jupiter

Jupiter is the fifth planet from the Sun and the Solar system by size planet within the Solar System. It is two and a half times as massive as all of the other planets in our Solar System combined....
, Saturn
Saturn

Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn, along with Jupiter, Uranus and Neptune, is classified as a gas giant....
 and Saturn's moon Titan
Titan (moon)

Titan or Saturn VI is the largest natural satellite of Saturn, the only moon known to have a dense celestial body atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found....
.