The Azores High also known as North Atlantic (Subtropical) High/Anticyclone or the Bermuda-Azores High, is a large

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

semi-permanent centre of high atmospheric pressure typically found south of the Azores in the Atlantic Ocean, at the Horse latitudes. It forms one pole of the

North Atlantic oscillation The North Atlantic Oscillation (NAO) is a weather phenomenon over the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level (SLP) between the Icelandic Low and the Azores High. Through fluctuations in the ...

, the other being the

Icelandic Low The Icelandic Low is a semi-permanent centre of low atmospheric pressure found between Iceland and southern Greenland and extending in the Northern Hemisphere winter into the Barents Sea. In the summer, it weakens and splits into two centres, one ...

. The system influences the weather and climatic patterns of vast areas of North Africa and Southern Europe, and to a lesser extent, eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. The aridity of the Sahara Desert and the summer drought of the

Mediterranean Basin In biogeography, the Mediterranean Basin (; also known as the Mediterranean Region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and w ...

is due to the large-scale

subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope move ...

and sinking motion of air in the system. In its summer position, the high is centered near Bermuda, and creates a southwest flow of warm tropical air toward the

East Coast of the United States The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the coastline along which the Eastern United States meets the North Atlantic Ocean. The eastern seaboard contains the coa ...

. In summer, the Azores-Bermuda High is strongest. The central pressure hovers around 1024 mbar ( hPa). This high-pressure block exhibits

anticyclonic An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from abov ...

behaviour, circulating the air clockwise. Due to this direction of movement, African eastern waves are impelled along the southern periphery of the Azores High away from coastal West Africa towards the

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Se ...

, Central America, or the Bahamas, favouring tropical cyclogenesis, especially during the hurricane season.

Variations

Research into global warming suggests that it may be intensifying the Bermuda High in some years, independently of oscillations such as ENSO, leading to more precipitation extremes across the Southeastern United States. Latitudinal displacement of the ridge is also occurring, and computer models depict more westward expansion of the anticyclone in the future. However, during the winter of 2009–2010, the Azores High was smaller, displaced to the northeast and weaker than usual, allowing sea surface temperatures in the Central Atlantic to increase quickly.

References

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High High may refer to: Science and technology * Height * High (atmospheric), a high-pressure area * High (computability), a quality of a Turing degree, in computability theory * High (tectonics), in geology an area where relative tectonic uplift ...

Anticyclones Regional climate effects Atlantic Ocean Climate of Portugal

Variations

See also

References