TheAzores High also known asNorth Atlantic (Subtropical) High/Anticyclone or theBermuda- High, is a largesubtropical semi-permanent centre ofhigh atmospheric pressure typically found south of theAzores in theAtlantic Ocean, at theHorse latitudes. It forms one pole of theNorth Atlantic oscillation, the other being theIcelandic Low. The system influences theweather andclimatic patterns of vast areas ofNorth Africa,Western Asia,Southern Europe, and to a lesser extent, easternNorth America. The aridity of theSahara Desert and the summer drought of theMediterranean Basin is due to the large-scalesubsidence and sinking motion of air in the system.
In its summer position, the high is centered nearBermuda, and often referred to as the Bermuda High. In the Northern Hemisphere summer, the Bermuda High often migrates in the area between Bermuda and the East Coast of the United States. When the Bermuda High moves closer to the United States, this creates a deep southwest flow of hot and humid tropical air toward theEast Coast of the United States. In summer, the Azores-Bermuda High is strongest. Thecentral pressure hovers around 1024mbar (hPa) often between Bermuda andNorth Carolina. Seasonally, the Bermuda High exerts its influence on the eastern United States between late May and October.
This high-pressureblock exhibitsanticyclonic behaviour, circulating the airclockwise. Due to this direction of movement,African eastern waves are impelled along the southern periphery of the Azores High away from coastalWest Africa towards theCaribbean,Central America, or theBahamas, favouringtropical cyclogenesis, especially during thehurricane season.
Research intoglobal warming suggests that it may be intensifying the Bermuda High in some years, independently of oscillations such asENSO, leading to more precipitation extremes across theSoutheastern United States. Latitudinal displacement of the ridge is also occurring, andcomputer models depict more westward expansion of the anticyclone in the future.[1][2] However, during thewinter of 2009–2010, the Azores High was smaller, displaced to the northeast and weaker than usual, allowingsea surface temperatures in the Central Atlantic to increase quickly.[3]
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