Siberian High
The Siberian High is a massive collection of cold or very cold dry air that accumulates on the Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

n 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
An anticyclone is a weather phenomenon defined by the United States' National Weather Service's glossary as "[a] large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere"...

 is often lower than -40 °C. The sea-level pressure (atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

) is often above 1040 millibars (30.7 inHg). The Siberian High is the strongest semipermanent high in the northern hemisphere and is responsible for both the lowest temperature in the Northern Hemisphere, of -67.8 °C on 15 January 1885 at Verkhoyansk
Verkhoyansk is a town in Verkhoyansky District of the Sakha Republic, Russia, situated on the Yana River, near the Arctic Circle, from Yakutsk. Population: There is a river port, an airport, a fur-collecting depot, and the center of a reindeer-raising area....

 and the highest pressure, 1083.8 mbar (108.38 kPa, 32.01 inHg
Inch of mercury
Inches of mercury, ' is a unit of measurement for pressure. It is still widely used for barometric pressure in weather reports, refrigeration and aviation in the United States, but is seldom used elsewhere....

) at Agata, Siberia on 31 December 1968.

The Siberian High affects the weather patterns in the higher latitudes of the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

, as far as the Po Valley
Po Valley
The Po Valley, Po Plain, Plain of the Po, or Padan Plain is a major geographical feature of Italy. It extends approximately in an east-west direction, with an area of 46,000 km² including its Venetic extension not actually related to the Po River basin; it runs from the Western Alps to the...

 in Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

. It may block or reduce the size of low-pressure cells or cyclone
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. Most large-scale...

s and generate dry weather across much of the Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

n and Canadian
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 landscape. The Siberian High is responsible both for severe winter cold and attendant dry conditions across most of Siberia. During the summer, the Siberian High is largely replaced by a low-pressure system, resulting in a summer precipitation maximum across almost all of Siberia. In general, the Siberian High pressure system begins to build up at the end of August, reaches its peak in the winter, and remains strong until the end of April.

See also

  • Siberian Express
    Siberian Express
    Siberian Express is a shorthand meteorological term in the United States describing the arrival of an extremely cold air mass of Arctic origins. It does not necessarily refer to an origin in Siberia...

  • Arctic dipole anomaly
    Arctic dipole anomaly
    The Arctic dipole anomaly is a pressure pattern characterized by high pressure on the arctic regions of North America, and a low pressure on the Eurasia region. This pattern sometimes replaces the Arctic oscillation and the North Atlantic Oscillation. It was observed for the first time in the...

  • Cold wave
    Cold wave
    A cold wave is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temperature within a 24 hour period requiring substantially increased protection to agriculture, industry, commerce, and...

  • North American High
    North American High
    The North American High is an impermanent high-pressure area or anticyclone created by anticyclogenesis , a formative process that occurs when cool or cold dry air settles onto North America.North American Highs moves...

  • Polar vortex
    Polar vortex
    A polar vortex is a persistent, large-scale cyclone located near one or both of a planet's geographical poles. On Earth, the polar vortices are located in the middle and upper troposphere and the stratosphere...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.